Get the extended wheelbase body if your rules allow it and the tungsten weights. The bodies, wheels and axles are all BSA approved from BSA kits, they are just meticulously finished with tools and know-how that you admittedly don't possess.

Let your son paint it, assemble it, insert the weights, lube the wheels and race it. He will have ownership and feel great about it. You will also because the car will actually finish the race and look decent.

www.maximum-velocity.com is the best site IMO.