The Gimson GR01 14.4V want a tad more amps. I would advice a Scorpion XXL, or else the Botbitz controllers.

We use a Gimson GR01 9.6V/Scorpion XL combo, and it moves well, is very controlable, but doesn't have an abundance of power.

I know, a tad more expensive; on the other hand, all the XXL's and XL's Team RCC has in use didn't fail us. Except 1 time, and that was a bit of swarf , after removing the speedo worked again.

Concerning batteries. LiPo batteries ain't as expensive anymore, and the more strick rules don't offset the advantages.

A 4S ( 14.8V) 3000 mAh pack costs between £20 and £45 delivered at your door.