Yeah sorry about the 400kg thing, I got that off this site who owned a busa set up for the drags with a whole lota extra stuff on it that pumped out 500hp.
And if I were to do it the car would be about 600kg. (KB10)
From the research that I have done there are a few of ways of doing it.
1) You could put the engine in the back like the minis
2) You could use the inbuilt clutch and gearbox off the busa, mount it north/south and weld one side of a universal joint connecting to the drive shaft onto where the front sprocket usually is. The trouble with this is that you would have no reverse. The aussie racing cars have some kind of mechanism in the diff...
3) You could not use the gears and clutch off the busa engine, but instead mount the shaft straight into the normal car clutch/gearbox, giving you reverse.
Its probably crazy and will never happen, but it would be one sweet as car. I think I might stick to my a14