The pack they guy ran that Kansasracer is refering to is a Tanic Pack. He went .2-.3 tenths a lap faster with the Lipo then his Nimh. Here's the pack he ran
Tanic rc car packs .You would only need two packs for the whole night. They can be charged at 5-6amps with the right charger. The Astroflight is a good one if you can find them for sale. The airplane and heli guys are buying them so fast the supplier cant keep up. Lipo is the future... Just wish someone would put out a good brushless to go with them.