May I ask where you found that motor and how much it's going to cost? I've looked at similar motors on ebay but the largest of that style that I've seen is 1000watts and the controller was a little on the pricey side.
What I'd really like to do is run a golf cart motor like this guy did:
http://neurotikart.com/
There's one ebay retailer selling used golf cart motors for $80. The controller will run over $100. The biggest problem is that golf cart motors have an open face on the output side and no bearing. You have to machine a custom faceplate to hold the bearing and the output shaft. His web site has lots of detail though. A definate 'must read' if you're entertaining an electric cart.