ahh well my point was gonna be that a 165 chip will let it boost to 15psi, a 195 to 18 i think (not 100 % on the 195) but with your spec i shud imagin you'd what to take advantage of more that 15psi

run it at over 15 mate, if it cuts its a 165 (or 15psi as i pref to say) if it dont its a 195

the boost limit seems to be teh only difference in my experiencs

you could just get it reflashed for 50 quid by a superchips retailer if it is just a 165