CCHOUSEKY

I've got an '06 FZ6 and I've tried everything from 87 to 93. I do notice a difference in the two. When I put the 87 in, I noticed a knocking in the engine. Nothing too bad, but it still wasn't something I wanted all the time. Now I always use 93 octane (I live in Kentucky). I would say go with the highest grade you can find. The little bit of extra cost is worth the piece of mind.