E303 and 1.6RR or the stock cam with 1.7RR. I have port matched gt40 upper and lower. 70mm TB and spacer. 70mm mass air. MaC lts. And was thinking of Gt40p heads. Thats what brought about the question.
stock will have more power before 3k rpms, e303 will make more top end.. You might notice a slight decrease in top end (I did), but you will out right know the difference in the lower-mid range power. I went from e303 1.7rr to stock ho 1.7rr. Im happy with my choice. Brought the power band lower, and its much more stout if you acclerate from idle to 5500. But if you are accelerating from 3000-5800.. the e303 might have more ave power in that rpm range. Its a trade off, but personally.. I dont regret sacraficing alittle top end power for an extra 2500rpms of usable power.