 Mostly I'm concerned about, well, I'm concerned about all of it, but, you know, their work for carbon deposits and corrosion from moisture. Shell V-Power Nitro plus premium gasoline is one of the best out there, if not the best. So by all means, but Shell's the gas for me. I run it on 93 octane all day long. Never have any issues. The engine's 12 years old now.