here is the rule for na you want high compression for power and for turbo you want low compression so your motor does not detonate. i belive the b18c1 has a stock compression of 10.0:1. that is most likely to much for alot of boost but i am not an expert on boosting. just remeber that if you are looking for a lot of boost you need to put some forged internals in the motor. i hope that helps you out some. more info is availible through carefully searching HAN fourms