I'm running 20 psi with 0 knock and I'm going to try out 21 psi to see if I can eke out another 5-10 hp. Gains get a lot smaller per psi going above 18 psi. But I'm on a decent size front mount. On the sidemount I couldn't push more than 15 psi without getting some knock from heatsoak in 4th gear.

I would keep it at 15 psi until you have a logger and a tuning device, then see if you can get it tuned in at higher boost.

Ender- I don't know if a 1g NT FPR will fit on a 2g. 2g guys, aren't the rails different?