think he means 3 bar MAP sensor, not 3 bar boost

it's better to use a 3 bar MAP as the ecu can then see what the boost is rather than guessing (as a gunship midrange boost is higher than the standard 2 bar one can read). by using greys (or dark greens) with that conversion, you don't have to run higher fuel pressure like you do with yellows to get enough fule flow at the higher boost (higher fuel pressure = more load on fuel pump and wiring)