doesn't have to be obnoxious or anything. just something to give a lil animation to add to the acceleration. heck audi's are a very classy car and they even get to get in on the fun.
one of my personal favorite sounds...
S4 Supercharger Whine - YouTube
i should prolly stop going off on this useless tangent now, just thought i wouldn't be the only one that missed a lil of this old school roots sound