This is a common complaint on P5s, so I can see how it could be an MP3 issue as well. Of course they weigh more and don't have your awesome ECU (+10HP) but I think it's more about the fact that 130-140HP isn't really that much, so big drive accessories like the A/C sap a larger percentage of the power than they would on a 300HP V8. Windows down, A/C off FTW.