The B58 sounds good from the factory, and a cat-back makes it sound like it should. Exhaust parts after the downpipe are mostly about sound and weight: expect a few horsepower on a tuned car, not a big jump.

Touring vs Track: resonated or "touring" systems keep highway drone down; non-resonated "track" systems are louder everywhere. Valved systems (Dinan, Akrapovic, factory M Performance) let you switch between the two. Mid pipes and resonator deletes are the cheap way to add volume to a factory system.

Exhausts are chassis-specific, so filter by your car or use the VIN lookup. Looking for downpipes? They're on the downpipes page.