Build Go Kart Motorcycle Engine Go Kart Road Legality...?

Go kart road legality...? - build go kart motorcycle engine

Hello everyone, I hope he will soon begin construction of a go-kart at the beginning that I believe gives me the opportunity to get the specification approved motorcycle single vehicle (MSVA) plan by the United Kingdom.

The law says I can build a car with 3 or 4 wheels up to 250 pounds, but you can use only a 50cc engine or build more than 350 pounds and be allowed to drive a motor 20 hp.
In your opinion, is to achieve what is best for? Go-Kart 50cc pathos of speed and power, and if so, how do I build a machine of 350 pounds!?
I intend to mobile free kart new bat and helicopter gross Halo 3 (large wheels and heavy armor, etc.) and have a body that surrounds the driver.
That is, I still think it would be difficult to bulk up to 350 pounds, a construction of a frame structure which is solid at this weight.

Any help is welcome!