Now i havent done this or anythibk but just want to ask,

If a Impreza is Mapped on Optimax and you use Normal 95 ron will it do any damage, only reason i ask was i needed fuel today and my garage only had 95 but i wasnt sure if i should use it, so to be on the safe side i came back home and got my company car and used that,

Whats the score with using 95 then if mapped on Optimax?

 

The engine will be much more likely to Detonate under load/boost conditions.
You could add some octane booster to raise the RON rating to that of the Optimax to be on the safe side

Cheers