well done on the buy man sweet mint looking car

he prob uses an octane booster to reach higher octane than the crap petrol we get in this country. if u are near a maxol they have e5 fuel which makes import cars run great wit no need for octane booster. i think greenapple petrol station have started to use this aswell. the pump will be marked unleaded with a small e5 which is a small bit of ethanol mixed wit regular fuel ups the octane. i notice a huge difference when i fill up wit e5 in the impreza compared to normal petrol. i can speak for most of the lads on her that e5 rocks

as for mapping i owned a b4 for about 4 years never had it mapped and there wasnt a prob but it is recommended if you are going to drive her hard if not u should be ok