Mark, Why not try the SR20DE+T route, where you just get a DE & put a turbo on it, like you're 1st option. It seems you don't need to run a lot of boost to make these work making heaps of torque, & this should work in nicely with the restrictor plate. DE's seem to be pretty cheap to buy, & i bet a lot of the drift guys would have stock exhaust manifolds they'd have taken off sitting around. Running lower boost would also lower the engine bay temperature & give things a longer life. I know the DET engines have some things different to the DE, but i think the cranks are the same.