I'm thinking of getting my head ported and polished, and throwing in some cams (I'm not sure if I want to do 256 or 268 yet) and valve springs. Also, I'm planning on doing a dry NOS setup. What kind of gains should I expect from all this (without spraying), and would I need a custom mapped chip to do all this? Also, how much should I expect to pay for the P&P? Thanks in advance.