the 3000 ni-mhs do'nt like being discharged rapidly , i used a set for flying electric planes and they worked fine , i used them in my sintra 700 with a 11 triple motor and no limit m-troniks speed controller and got 2 runs and i was charging them with a supa-nova charger that was recommended , i would use ni-cads the ones the car racing boys use as they are made for rapid discharge, i used to race cars both eletric and nitro, if using a modified motor i would recommend a no motor limit speed controller, check out
www.modelsport.co.uk, they race cars and have a vast selection of motors, batterys and speed controllers, hope this helps.
paul