I like my 2871, but my current goal is to try and make as much power as possible at 12 psi. Crazy enough, even at 12 psi with this car I *rarely* run into anything that requires more boost.
Built motors are still prone to detonation just like a stock motor. Unless you're running a big turbo and/or race gas, anything past a certain psi level out of the efficiency range of the turbo isn't good. For me, that's 17psi. I've never taken this turbo over 17psi, but with a tank of race gas it'd be fun to see what 22psi does.
-G