You won't properly charge the pack at anything below 2A, just get 2 or 3 packs of 3700's which you can get for about 25 bucks a pack and charge them at 4A

Punch is the least of your problems if you're drifting on plastic, punch is for grip racers

Anything above 4A will see a slight increase in punch and a slight decrease in runtime but will reduce your cells lifetime - NiMh's DON'T LIKE HEAT

Kev