OK I dont really know that much about oils (petrol)? but whats the difference. I own a Supra. My dad says regular unleaded is fine, and when I took my car for a test drive, it was almost out of petrol so they (the importers, the cheap bastards they are) filled it up with a little bit of regular unleaded as well. But since I've got it I've switch and just filled it with the 95 octane (i think thats what it said) or premium. I havent driven it that much yet so I've only filled it up once. While one of my friends who own a WRX says he wont fill his car up unless its with something Optimax??? (sorry forgot whats it called) Whats the difference with the petrol and is it different for different ptrol station and am I doing the right thing, filling up with premium stuff? Sorry if this sounds like a stupid question. Thats why I'm asking.