76 on Pico blvd. has racing fuel(west LA), thats actually were i go to get gas. i fill it with 91 then put about 1/3 100 octane, rounds it out to around 94-96. the only down side is that its about $5.00 a gallon ! soooooooooo it can get a little pricey to fill her up. but id rather pay a little more in gas then pay for a new engine ! i have a chip in my euro 91 m5 and never had any pinging. not sure if its the gas or not but runs smooth. i can actually tell the difference when i just fill up with 91, maybe its mental but she doesnt feel a light on her feet as she does with the mixture. throttle reponse seems smoother ? but maybe its just my imagination ! anyway thats my take on the subject.