Thats a good tip from Jonno.

I agree about wheelchair motors though, for a first try they are perfect, you don't have to worry about getting them geared up and can even use the wheels that the often come with. You just attach them how you want and you're away.
An earlier team heavy I was involved in, Cabrakan, ran on wheelchair motors and just won last year's best newcomer heavyweight award, so don't count them out as rubbish.