as above.

think about it.

a 2 bar MAP sensor gives an output of 5V at 2 bar (1 bar of boost + 1 bar atmosphere).

a 2.5 bar MAP sensor gives an output of 5V at 2.5 bar (1.5 bar of boost + 1 bar atmosphere).

so if you fit the 2.5 bar one, and have 1 bar of boost, the 2.5 bar sensor will only output around 4V, which your ecu will think is only 1.8 bar so not give you enough fuel for that amount of air.