i would phone c2, tell him your budget and what you intend to do and get some advice on what you need, they can sort you a spacer,mapping arp`s and prob more in one phone call. Kevs right though. 15psi is NICE i ran over 23 psi (1.6 bar) and look what happened , it went BANG. and i lost my whole engine,head,block,pistons,rods at a very big cost, cos i ran too much boooooost. 15 psi is a nats over 1 bar, on c2 software,that will be perfik. enjoy the boost