Highway Speed Whine
I've had my 2002 MP5 for almost two months right now. I've done a lot of fixes on it to bring it up to my maintenance expectations and I'm dealing with the little things. At highway speeds, there is a constant whine, possibly a whistle, that is only present with throttle application. The pitch goes up and down with speed. Once I lift off the throttle, the noise goes away. I've already gone from a cold to short air filter (keep the filter off the salt covered roads in the winter), plugs changed, oil and gear oil changed. I didn't install the aftermarket stereo that came with the car but I've read before in past installations of watching some of the wires crossing as to avoid a whine.
Any ideas?