Would it be possible to have some new header and muffler options?
Such as an unequal length header which produces a more rumbling exhaust note like found on WRX STis, and performance oriented mufflers which make the exhaust note louder and/or more aggressive.
Some new headers like unequal length headers are coming after the engine revamp which is a fair bit down the line and what you’re asking for is basically the straight through muffler that is already in the game.
I guess it does sort of line up with the straight through muffler.
However increasing the quality of the exhaust to increase power also reduces noise which doesn’t make sense with the straight through mufflers. But I can see how that would be difficult to code around.
Using a straight-through muffler rather increases both power (usually) and noise–this (or a high-quality exhaust with no muffler) is the in-game equivalent of a loud, performance-oriented exhaust. All else equal, lower noise is almost always better because it improves comfort, so increasing exhaust quality reducing noise makes sense.