Well, 3 of our owner/ops have purchased this thing and they all say it works. the one guy showed me his log and he went from 4.9 to 6.5 over a 3 month period, the other guys say they get about a mile to a gallon more. these are all C-15 cats.
anybody here tried it? I think I'm going to try it, they have a 30 day money back guarantee if you dont like it.