i agree with WCS on the turbo entirely. LS/VTEC's are becoming a very big trend and for good reason, there awesome combinations. people are doing it all the time and there are even a few that i have seen twin turbod. as far as naturally aspirated goes for one, go for it. 270whp on a naturally aspirated engine would be insane. have it properly machined and i wouldnt skimp on anything. if you have the cash get an individual throttle body setup for NA.

i on the other hand prefer a turbo over NA. you could probably build a turbo kit from 2200 and up.