One of the best quotes I have taken from HAN over the years is this: "The most work anyone should ever do on a D series motor is taking it out." True, it's possible to bring a D series motor to the 300 hp level, but why would you want to? It would take so much time and money that starting out with a B series motor as a platform to begin with would have been an economical and more logical decision. In order to boost the D to that level you'd have to lower your compression, bulletproof your block and head with forged internals and most likely get a stand alone computer. My prognosis: B16 head, B20 block, boost, win... teh end.

Edit: And please boss, I need you to understand that the passion of racing shouldn't revolve around the obsession of beating a single type of car but rather the ability of an ordinary car to do extraordinary things. You just gotta be able to work and tune your car and enjoy the fruits of your labor because if you set your heart on unrealistic goals, it'll seem like everything you have done was all in vein.