motor size

Jamie where do you get the belt and cogs for the timing belt?

you can get them off technobots or RS (although RS will be ridiculously more)

Surely you can get timing belts and cogs from any Car hardware store?

i've found they are considerably more expensive and heavier than the ones of technobots

You probably can do however they are likely to be made from steel and won't come in the assortment of sizes