Aaron at SDPC

Cylinder heads or a nitrous kit would be my suggestion then. I would probably spend the money on a set of cnc'd stock castings or aftermarket castings. That will be worth typically 25-40rwhp depending on whos doing the work and what casting it is. If you go the nitrous route you will be in it for about the same money but have the ability to make another 100-150 horsepower without much worry.