OK, ive stopped using optimax after my 3rd tank. It made the car weak, and i had problems shifting in high rpm and low rpm, i mean it was hard. I used up that tank, i nearly went to toyota to throw the keys into their face. I filled up with Mobil synergy, and the car was soo much different, smooth, easy to shift, power back etc. Bad fuel puts more strain on engine components, increases vibration, harder to shift. Ive used Bp ultimate, its ok, but synergy 8000 is the fuel i always use, id rather ***** in the tank then use optimax. Thats my personal opinion, you guys use what you like, but anything under 98 octane, not for me.