No, no aftermarket stuff that I know of (this thing cant get much better than it is!). Oddly enough I got two brand new front tires last night and either these tires are LOUDER than the previous ones, or something is weird, because while the noise is still there, it is not pronounced now as it was before (though it is certainly engine sound, not driveline noise). The best I can describe it is this way... It doesnt sound like a knocking or anything normally associated with any sort of engine problem, but if you had to listen to it for hours on end youd get a headache... pushing it slightly over this 2500RPM point, or cruising slightly under this point results in a quiet ride.
Ill have to try and record the sound somehow when I get a chance.
<img src='http://members.cox.net/inelson5/330i.jpg' border='0' alt='user posted image' />
<img src='http://members.cox.net/inelson5/wooani.gif' border='0' alt='user posted image' /> The whistles go WOOOO!!! *BUBB RUBB FAN CLUB*