If it's a stock B16, there is a knock sensor on it assuming that no one has removed it and it hasn't taken any damage in transport. If that's the case, a P30 ECU is your best choice; I'd really recommend using the knock sensor for safety. It's not the greatest knock sensor, and it can get confused by the resonance of some types of aftermarket pistons, but it's a great safety net on a fairly stock engine. The P28 ECU is the exact same ECU as a P30, but the P28 lacks the knock sensor board. The stock program in the P28 is obviously different, which is why it needs to be chipped with a B16 program if you want to use it.