Changing ECU from WRX to STI, is it possible?
 

Hello guys, as it says in the title can I just swap my V1 WRX ECU for a V1/2 STI ECU? I am looking to up the power but only being a WRX I am undecided wether I should go all out and get an Apexi and a custom map, @ £500-£600 or just get a Prova or similar @ £100-£200.
What is reliably achievable from a WRX around 300 bhp? is the Apexi just overkill?
Cheers

Apexi and custom map TBH.