oh yeah , that would be a tough beast to control on the trails. i only ride the oregon dunes. i have seen a lot of street bike powered quads. they rip out on the dunes, but thats the only place i would want to ride them.
i think an xs650 would be great in a newer quad frame(like and ltr, trx450r, or the yfz450), plus you dont have to worry about ground clearance in the dunes so much. the ones i see alot of the time are running really big 22"
paddles or 25" paddles.
if your zipping around in the woods or trails i would say keep the warrior motor, but if its for the dunes go with the gixxer.