14.5 psi is 1 bar to be more precise and so 12.5psi is 0.86bar, but the fuel cut level can vary slightly as its actually the map sensor voltage level which triggers it not the pressure, plus if your boost gauge isn't 100% accurate then its hard to say exactly when it occurs. Basically running 0.8bar should be ok, but as sparky said the colder denser air will increase the pressure and you'll be more likely to hit fuel cut, on the glanza's the engine management light should flash just before you hit it as a bit of warning, since its not good fof the engine to bouncing off it regularly. Also I wouldn't get an fcd without some form of fuelling and rolling road session to then get it spot on. Nice car though mate, good luck with it.