Will Sti ecu make my rs legacy go any better

[rwcoop]

I have a 1990 single turbo quadcam engine in my jet boat. It is standard out of an RS Legacy. (jap import)
Ive bought a 94 wrx sti ecu and plan to swap it with the rs one. It has the same plugs (4 plug)
I realise the boost cut is higher but this makes no diff as i have an after market boost controller??
Will this make it go better or will I cause damage to the engine??
look forward to replys!!