Thought I would chime in here, I bought my SVT three months ago, I drove it home to AZ from New Orleans, anyways on the way back I used mostly 91-93 octane but for two fill ups i put in 87, I got about twenty miles less per tank, so in my mind it's worth the 2-3 dollars for the 91......I do have a good friend that bought a 99 SVT brand new and has run 87 from day one and hasnt had any problems with it and he has put almost 120k on it now, so it really comes down to the saying here that you have to pay to play......
