S58 Downpipe Install: G80 M3, G82 M4, G87 M2, X3 M and X4 M

Short answer: The S58 has two turbos, so you're swapping two downpipes, two turbo gaskets and four oxygen sensors. The job is done mostly from underneath. You drop the underbody trays and the center brace, support and unbolt the mid pipe, release a V-band at each turbo, and fit the long pipe first. Plan on 2.5 to 4 hours on a lift and a full weekend on jack stands. xDrive cars are harder because the front driveshaft crowds the short pipe. Every S58 car needs a tune that supports the pipes, and on the G8x cars that means a DME unlock first.

Parts and tunes in this guide are for off-road / competition use only. Not legal for use on public roads in the United States, including California.

I'm Gleb Blekher. I run B58 Racing out of Dallas, TX. We sell S58 downpipes from Spool, Active Autowerke, Fabspeed, CTS Turbo and Capristo, and the install is the first thing buyers ask about. Downpipe makers publish less for the S58 than for the B58. Several don't include instructions at all. So this guide pieces the job together from the sources that exist: owner DIY threads, retailer install notes and the factory fastener torques that Mishimoto quotes in its G80 instructions. Where I couldn't confirm something, I say so.

Who this guide is for

Car	Chassis	Drive	Notes
M3, M3 Competition	G80 (G81 Touring)	RWD or xDrive	2021 on
M4, M4 Competition	G82/G83	RWD or xDrive	2021 on
M2	G87	RWD	2023 on
X3 M, X4 M (and Competition)	F97/F98	xDrive only	Different downpipes from the G8x cars

The G8x cars (M2, M3, M4) share downpipes with most brands. The X3 M and X4 M use their own pipes. Spool, for example, says its G8x downpipe doesn't fit the S58 SUVs. Buy the version for your chassis.

Difficulty, time and whether you need a lift

Difficulty: 3 out of 5 on RWD, 4 out of 5 on xDrive. These are OneFastShop's ratings, and they match what owners describe.
Time: 2.5 to 4 hours on a lift for an experienced hand. For a first-timer on jack stands, plan a full weekend. One G82 M4 owner who rated himself novice to intermediate and worked alone on a low-profile jack and stands said it took several days.
Lift: strongly recommended. You can do it on four jack stands, but the pipes are long and the mid pipe has to come down. A lift and a helper save hours.
xDrive: the front driveshaft and front axle housing crowd the short downpipe and the bolt that joins it to the mid pipe. A 2024 M3 Competition xDrive owner fought that bolt for days before a crow's foot on a long extension with a flex-head ratchet got it out.
X3 M / X4 M: we could not find a published step-by-step for the F97/F98. One seller notes that no instructions are included with its pipes and recommends a professional install. If you have an X3 M or X4 M, read the sheet from your pipe's maker. If there isn't one, pay a shop that has done the job before.

Tools

Sockets 8 mm to 16 mm, plus 21 mm. OneFastShop lists 8 to 16 mm. A Bimmerpost DIY lists 16 mm and 8 mm for the belly pan and under trays. Mishimoto's G80 instructions use 10 mm for the plastic trays, 16 mm and 21 mm for the large aluminum underbody tray, and 13 mm and 15 mm for the upper strut brace.
13 mm for the exhaust hangers near the center brace (Bimmerpost DIY)
O2 sensor socket
Long extensions, a flex-head ratchet and a crow's foot for the short downpipe's mid-pipe bolt
Pry bar for V-band clamps that stick to the flange
Torque wrench (3/8" and 1/2" drive)
Transmission jack, second floor jack or tall stand to hold the mid pipe
Penetrating oil, high-temperature anti-seize, gloves and eye protection
Masking tape and a marker to label fasteners and sensors

Parts list

Every link below fits the cars listed with it.

G80 M3, G82 M4 and G87 M2:

F97 X3 M and F98 X4 M:

Gaskets. You need one turbo-to-downpipe gasket per turbo. Two retailers list BMW 18307553601, a 3.5" gasket, for the S58 turbo side, and OneFastShop calls it a single-use crush gasket. BimmerWorld lists a separate 70 mm gasket, 18308053348, for the joint between the downpipe and the next pipe back. Sources don't fully agree on which goes where, so confirm both part numbers with a BMW dealer using your VIN. Check whether your downpipes come with gaskets before you order.

While the exhaust is down: a mid pipe is the natural next step. Options include the Spool 4" mid pipe (M3/M4), the AWE non-resonated mid pipe, G8x and the AWE non-resonated mid pipes, X3 M/X4 M.

Browse downpipes (S58 pipes are listed there too) or everything for your car on the S58 parts page.

Step-by-step: S58 downpipe install (G80, G82, G87)

The sequence below follows a long Bimmerpost G80 DIY thread, as summarized by OneFastShop and in search results we could read. We added the underbody and brace fastener torques Mishimoto lists in its G80 M3/M4 charge pipe instructions. Bimmerpost blocked our direct access, so we couldn't read every post. Read your downpipe maker's sheet and follow it where it differs.

Stage 1: prep

Let the car cool completely and park it on a level surface.
Soak the hardware. The night before, spray penetrating oil on the V-band clamps, mid-pipe bolts, hanger nuts and all four O2 sensors.
Disconnect the battery. The G80 battery is in the trunk. The DIY thread disconnects it because the starter sits close to where you'll be prying. Mishimoto also recommends disconnecting the negative terminal for its work on this car.
Raise the car on a lift or four jack stands. Never work under a car held only by a jack.
Label everything. The M4 owner who spent several days on his install said his top lesson was to label every fastener, because there are dozens.

Stage 2: removal

Remove the engine cover and the upper strut brace. Mishimoto's G80 instructions remove the cross brace and V-brace with four 15 mm fasteners and one 13 mm bolt.
Unplug the four O2 sensor connectors. Two of them are up top in the engine bay. One owner had to unplug the positive battery relay connections to reach an O2 connector hidden behind them.
Remove the underbody trays. Mishimoto's G80 instructions: the plastic trays come off with 10 mm screws, including three in each wheel well. The large aluminum tray has two 10 mm screws in each wheel well, two 21 mm bolts at the rear and eleven 16 mm bolts. Get a helper for the aluminum tray. It's big.
Remove the hangers and center brace. The DIY thread removes the single 13 mm nut on each of the two hangers between the center cross brace and the downpipes, then removes the center brace.
Support the mid pipe, then unbolt it from the downpipes. Use a jack under the exhaust so the rear sections and hangers aren't stressed. On xDrive cars, this is where the short pipe's joint gets tight.
Release the V-band clamps at the turbos. Remove each clamp bolt completely, then pry the clamp off the flange. OneFastShop notes the clamp tends to stay stuck to the pipe after the bolt is out.
Remove the downpipes. You can lift each pipe out with its sensors still fitted and swap them on the bench, as the DIY thread does. Or you can take the sensors out in the car first, as Palenon's guide does. Wiggle the pipes free gently. Keep clear of wiring and lines.
Save the rubber hanger flanges from the old pipes. The M4 owner found his new pipes needed them.

Stage 3: install

Move the O2 sensors to the new pipes. Label upstream and downstream for each pipe before they come out. Use the O2 socket, and put anti-seize on the threads only, unless your pipes or sensors come prepared.
Fit new turbo gaskets. Make sure no old gasket is left on the turbo flange.
Install the long downpipe first. The DIY thread also tightens the turbo-side O2 sensor before positioning that pipe, while there's still room.
Hang both pipes loosely. Start the V-bands and the mid-pipe joints by hand so everything can still move.
Align, then tighten. Raise the mid pipe back into place, refit the hangers and center brace, and check clearances to the driveshaft, subframe and body. Then tighten the V-bands, mid-pipe bolts and hangers to the values in the instructions supplied with your downpipes. OneFastShop says the turbo clamp torque is lower than most people expect. We could not find a published number we trust, so don't guess.
Refit the sensors' wiring away from the pipes and clip all four connectors back in.
Refit the trays and braces. Mishimoto's G80 values: large aluminum tray 21 mm bolts at 100 Nm (74 lb-ft) and 16 mm bolts at 56 Nm (41 lb-ft). Upper strut brace 13 mm bolt at 56 Nm (41 lb-ft) and 15 mm nuts at 28 Nm (21 lb-ft). Mishimoto's guide is written for the G80 M3 and G82 M4. If you have a G87, check the BMW spec for your car.
Reconnect the battery.

Stage 4: after the install

Leak check. Start it cold and listen at each turbo flange and mid-pipe joint. A tick at idle that fades as the car warms is still a leak. Fix it.
Scan for codes. Check for O2 sensor and catalyst codes before the first drive and after it.
Tune and coding. The car needs a tune that supports your pipes. On the G8x cars, retailers report the DME has to be bench-unlocked before it can be tuned, with the DME out of the car for one to three weeks. Order the unlock before the pipes go on, or expect a check engine light while you wait. Brands differ on catted pipes. Active Autowerke says its catted downpipes need no performance tune. CTS says Stage 2 software is required to avoid a check engine light. Fabspeed says its pipes don't set one. Race pipes need a tune with the rear sensors handled. One M4 Competition xDrive owner who tried O2 spacers instead of a tune got P0133 and P0145 right away with a rough idle. Don't use spacers to cover a missing tune.
Recheck after a few heat cycles. Retighten clamps and hangers to spec.

Common mistakes and how to avoid them

Reusing crushed turbo gaskets. OneFastShop calls them single-use and says one owner's came off flat. Order two with the pipes.
V-band clamps clocked where you can't reach them. Before tightening, turn each clamp so the bolt points where a socket can reach it from below. A mis-clocked clamp is hard to torque evenly.
Tightening the turbo end before the mid pipe is aligned. That preloads the pipe and causes leaks at the flange. Hang everything loose, align it, then tighten.
Mixed-up O2 sensors. Four sensors and four connectors. Label them and move them one at a time.
Wires touching the pipe. Route and clip every sensor lead away from the exhaust.
Heat shields and trays left loose. Refit every shield, hanger and tray you removed. A loose shield rattles under load.
Blaming the downpipes for wastegate rattle. Owners on the G80 forum describe a "keys in a can" rattle around 1,800 to 2,000 rpm when the car is hot, and say dealers often can't reproduce it. Louder downpipes can make an existing noise easier to hear. Check shields and hardware first, then have the turbos inspected.
Driving it hard on the stock map. Expect codes and less power. Have the tune ready.
Fighting the xDrive short pipe with the wrong tools. Get a crow's foot and a flex-head ratchet before you start, not halfway through.
Checking your build year. Owners report BMW changed some exhaust hanger hardware on 2025 cars. Look at your car's fasteners before you start so you have the right bits.

FAQ

How long does it take to install S58 downpipes?

About 2.5 to 4 hours on a lift for someone experienced. A first-timer on jack stands should plan for a weekend or more.

Is the S58 downpipe install harder on xDrive?

Yes. The front driveshaft and front axle housing crowd the short downpipe and its bolt to the mid pipe. Owners report needing a crow's foot, long extensions and a flex-head ratchet. Many owners pay a shop for xDrive cars.

How many gaskets do S58 downpipes need?

At least two turbo-to-downpipe gaskets, one per turbo. Retailers list BMW 18307553601 for the turbo side. Confirm with your dealer by VIN, and check whether your pipes include them.

Do I need a tune after installing S58 downpipes?

For race pipes and most high-flow cats, yes. Active Autowerke says its catted pipes don't need one. On G8x cars, the DME needs a bench unlock before any tune, so plan for that time.

Do G80 M3 downpipes fit the X3 M?

No. The F97 X3 M and F98 X4 M use their own downpipes. Spool says its G8x pipe doesn't fit the S58 SUVs.

Will S58 downpipes cause wastegate rattle?

The pipes don't change the wastegate. Some G80 owners report a hot rattle around 1,800 to 2,000 rpm, and a louder exhaust makes it easier to hear. Check heat shields and hardware first.

Planning the rest of the build? See the S58 charge pipe install guide and the S58 parts page.

Sources

DIY sequence, xDrive short-pipe bolt, battery, labeling, hanger flanges, spacer codes, DME unlock, gaskets, time and difficulty: OneFastShop S58 downpipe install notes (onefastshop.com), summarizing Bimmerpost G80 "Downpipes install DIY" (we could not open the thread directly; 8/16 mm trays, 13 mm hangers and center brace come from search excerpts of it)
Underbody tray, strut brace and battery details with torque values for the G80/G82: Mishimoto MMICP-G80-21 install guide
General steps, sensor labeling, post-install leak check: Palenon Performance G8x downpipe install (palenonperformance.com)
Gasket part numbers: BimmerWorld S58 70 mm downpipe gasket 18308053348 (bimmerworld.com), OneFastShop 3.5" turbo-to-downpipe gasket 18307553601 (onefastshop.com), Pumaspeed genuine S58 downpipe gasket
X3 M/X4 M: no published step-by-step found; one retailer listing found in search says no instructions are included and recommends professional installation. Model-year coverage differs by brand: Turner Motorsport F97 downpipe listings (turnermotorsport.com)
Wastegate rattle reports: g80.bimmerpost.com wastegate rattle thread
Tune and check engine light claims by brand (Active Autowerke, CTS Turbo, Fabspeed) and Spool SUV fitment: manufacturer product information on our listings

S58 Downpipe Install: G80 M3, G82 M4, G87 M2 and F97/F98 X3 M/X4 M