The owners manual says BP. I've been using BP almost exclusively for the past 18 years, other than during some testing (see below).
Shell is the absolute worst gas you can get. The additives cause knock. I've been working with DiabloSport for the past 7 years, and done tons of logging and testing, on multiple different types of motors; Naturally Aspirated, Supercharged, Turbocharged, Port injected, Direct injected, Pushrod, OHC, etc. Shell will almost always cause knock, while other good fuels don't. Since the base fuel is the same, the only explanation is the additives. Cleaners don't burn, and apparently Shell's additive package has too much of them.
I'd rather have some carbon on the backs of my valves than a hole in the top of my piston. Seemingly, Shells chemists don't agree.
