Blaze
Best thing you can do is get a 4 to 1 gearbox ( Ignore the pic, its wrong and I have to update it ) http://shop.immortalhobbies.com/Stee...8758875888.htm
then a set of the 480 motors http://shop.immortalhobbies.com/480-...210121480M.htm
If purchased from my site I will pull the pinions off the stock gears and replace them on the new motors correctly so the motor shafts are not bent.
Changing the pinion alone will not do much to help achieve the goal of more torque, Changing just the motor will not help enough either. Especially if you have metal tracks and lots of metal parts
What you need to do is change the stock gearing AND the torque and rpm input of the motor driving the gears. The 4 to 1 steel gearbox is a good investment especially if you have a Tiger/KV, King or any of the bigger tanks, the 480 motors will amaze at how much power they have.
Because the JP is turretless you need even more torque just to spin to align your shots. The combo offered above will more than satisfy your requirement