Imo stay away from 5th injector set up and go for aftermarket management, cossie, omex, pectel, megasquirt etc ported & polished head, newman cam & solid lifters, stage 2 or 3 turbo, grs, radtec or airtech front mount cooler all my opinion of course and if your engine is healthy you should make very good power from the above mods, and dont think a standard turbo would last long at 18 psi mate