RE: LI-POLY POWER - I THINK I FIGURED IT OUT!!
An 8S LiPoly will be a bit more than a 24-cell NiCd. In fact, it will be close to 27 NiCd cells. Each LiPoly cell is good to replace about 3.5 NiCd or NiMH cells. If it were me, I'd probably go with a 7S2P. It's the equivalent of 23 cells, and you're pretty much assured that you're not going to overstress the motor. I've heard rumors that you don't want to spin an AXi faster than it was designed to go, or draw more than the recommended amount of current. Besides, it'll save you about $42 and almost 4oz of weight.