Yeah, huge difference in the fuels if you are willing to push the limits of each fuel. For instance. If I even dared to run the amount of timing down the straits of the half mile oval that I did on the C14 with the C12, it would be a detonation disaster. I also noticed that the bike does consume way more of it, so additional jetting is a must. I was checking plugs every two or three laps to finally dial it in. Also, the Q series stuff does run a bit cooler.