It means you should be tuned for the meth if it’s m1. That’s because the engine should know about the octane. However if you are looking for mainly cooling then run wm50
I installed one of these about a month ago. Totally forgot about the o-ring because I didn’t even look. Glad I didn’t need it
Édit: took me about an hour to install
$1/gallon of methanol? Doubt
Wm50 mix cleans cylinders, provides some octane, and lowers temps. Spraying m1-5 is rough on lines, pumps, and seen as unsafe for most because of uneven distribution of an inline 6. Zerk has used meth for octane temporarily but that’s not recommended by most...
I’ll throw my experience in here for transparency aswell. Never purchased anything from Marshall directly, although I have purchased Visconti items through other dealers. Marshall did the favor of giving the overview of my experience all summarized in one thread...