Thanks for the response, do you know what power gains you got with the PRO-ALLOY ?

I'm currently getting 194 bhp at 12.5 psi on a Forge Motorsport IC (and a few other mods) which is very similar to the standard S1 job. My problem is that I don't want to start cutting the shell. I've got an ACT gauge to fit so I'm going to look at temps and then wind it up to 15 psi and see how the current IC copes.

Colin.