Learn what a catless downpipe smells like, when odors peak, and how five checks can help spot cabin leaks, plus owner reports and U.S. emissions rules.

Compare slip fit and flanged exhaust joints with practical checks, tools, and durability tradeoffs, from calipers and band clamps to repeat service.

Learn why muffler deletes are not street legal in the U.S., what state rules mean for inspections and citations, and how valved exhausts offer louder sound.

Verify a CARB Executive Order for your exact performance car, check federal Clean Air Act rules, and confirm an exhaust fits before you buy.