Yes the otai here are all correct on their comments. Unless your Airtrek is recond from Japan, most we see on the road are imported locally by USF (I think) and they're mapped to run Ron95.
When mine was stock with no mods at all, I upped the boost from 0.6 bar to 1 bar and it ran for almost 3 years, not a hiccup.
4G63T in stock is a detuned version from Evo. You may think the 40hp lesser is not much but other than the block, almost everything else are different. Cams, injectors, intake manifold, turbo etc etc. In stock, you get about 180-190whp if your engine is healthy. 0-100 is around 8.5 secs just to be conservative. The spec-sheet claim of 6.5 secs is not possible. The INVECS II slow-box robbed huge hp from the engine. Additionally to make things worse, the car weighs over 1600kgs!
For ECU-remap and tuning, you can look for Ah Wah if you're living in Klang Valley (contact on pinned thread). He specializes in Evos and Airtreks. Congrats and enjoy your ride!