This question is very general. At the end of the day it comes down to what you want to do with the car. If you want to stay all motor or go forced induction. As far as being all motor, out of the motors you mentioned, the K series would render the most power over the older h's and b's. I'm not saying in any way that the h's or b's can't hang with the k's, but it's just a whole nother monster. new technology, better tuning material etc..Is it a daily driver or is it a straight track car? How much exactly is your budget? You need to do a bit of research before you go dumping thousands down the drain. the more information you give us about what you wanna do, the better we can guide you.