7XL Vs 8L on 12 cells..which is better?

[Rtsbasic]

So the general concensus is that a 7XL runs cooler, draws less amps so easier on controller, has more torque in general, and if geared appropiately will hit a higher top speed than an 8L in spite of revving a lot lower (29,000rpm on 12 cells vs 41,000rpm), while not really affecting runtimes? The bit that confuses me, is the 7XL generates more power, while pulling in less amps than an 8L, you can only put out what goes in, and the efficency difference can't be that big can it? Or is it possible for it to pull the same number of amps but because the bigger surface area and larger rotor its able to do it without heat problems?

Which brings me to my next question :) What sort of top speed is realistic to hit with a 7XL on 12 cells? Mtroniks say a stock weight emaxx will do 50mph with their 8L/Truck ESC combo on 12 good cells, but I find that a bit hard to believe. In summer I go to a local bash meeting every weekend thats held on a very big field, so lots of top end is important to me when I go to this (mostly because there's only about 3 of us that run electric..against 20-30 nitro buggies and trucks, lagging behind some dudes stock savage would suck).