K&N panel filter will make the same noise as a standard filter (I think), people say you get a sportier noise from induction kits, but tbh I cant tell the difference
Exhaust systems like jetex and magnex are nice, they sound pretty standard at normal driving and only get louder when you boot it. They also cost quite a bit though

but then again so does a decent induction kit, I've used cone filters before and I think the only affect you get is placebo