I've done some pretty specific testing on gas mileage with and without the A/C. I have to say even though I didn't belive it the theory that the windows down create more drag than the A/C it's probably true. I get just as good mileage with the windows up and the AC on as with the windows down and AC off. I think that shock when you turn on the A/C (or the defrost) is what has everyone thinking it's a very nasty power drain. (I'm not arguing that it doesn't take power) Best solution is to turn it off when you want to pound though the gears and then turn it back on when you are done. Many cars disengauge the A/C and WOT anyway.