if you were to swap out a map sensor you would need to account for the sensitivity difference in the ECM. The sensor outputs XXXX mV/bar so simply putting in a higher range sensor would do one of two things. It would have a different sensitivity (most likely) and the output at lets say 5V would be 4 bar where as the stock one would be 5V 3 bar. basically it would be reading low all the time because it has a lower sensitivity. The second thing that could happen is that it has a different voltage range all together so 5V would still be 3 bar, but 6.666V would be 4 which the ECM would interpret as invalid since the sensor should only be able to output 5V, or what ever the peak may be. If you could get one of the tuners on your side that would be the way to go for sure, but without it I don't forsee much in the way of gains.
