[dhoggm3]

Shell and Chevron have cleaners in then that will help keep the injectors clean. No difference in the short run. Big difference in the long run. Or you can just dump in some Techron injector cleaner from time to time. At that point, it's just about octane.

Don't buy gas when the tanker truck is there. It stirs up deposits that don't get along well with your M3's fuel filter. Or any other fuel filter for that matter.