Not sure jamie, the magnet ive got is way OTT for the drive motors- it slows it down alot. I might try it with one half the size. But you are right with the exstra disk weight and speed it is probably going to be stupidly crazy to drive now... Although i kinda like it, it looks cool. Plus magnets weigh quite alot... I think ill just see how much the complete robot weighs when its back together and how crazy it is to drive then decide