[lincpimp]

A 1521 1y would be the best bet. I am guessing by 6000 20c you are refering to maxamps? No way that pack will stand up to a 1512, let alone a 1521. You need something good, like an enerland cell based pack. 5000 25-30c 6s lipo will do. FP, TP, polyquest, polyrc, neu energy and hyperion are what to look for. Mike also sells some packs under the rcmonster name that perform well.