If you decide to go all motor I wouldn't use a D unless you don't care about numbers and aren't aiming for much. If I was to do it again I would have just boosted my Z6. If I'm lucky I might make 160whp when it's all said and done. I also have a lot of $$$ tied up in my setup. Back on topic if you want a VTEC head I would use a Z6 like jdm94coupe said.