OK, so I was one of the guys who chopped off my stock 335d exhaust for an aftermarket one in hopes that it would produce a sportier, louder exhaust note. Nope, nada, no can do........a.k.a it didn't make a difference. Anyway, after having this aftermarket exhaust for 2 years now I must say that every time the ERG comes on to burn the NOX gasses while I'm driving the exhaust sounds much more noticeably louder. Nevertheless, after the fan goes off its back to being too quiet. I can't remember this happening with the stock exhaust. Anyone else with aftermarket mufflers notice this?