I did think about speed 900s, but then there is the problem of cost. Although not that expensive in themselves, they need a gearbox and decent ESC(s), neither of which I have. I need to finish this bot in 5 weeks, and would like to if possible use some pre-made motor-gearbox combos to save time. Can anyone think of anything like that which I can get hold of within the next few weeks, and won't cost a bomb.

Thanks