I love reading about snake oil. It's entertaining, and reminds me of all the big claims about the hydrogen generators
The thing about MMO having a bit of abrasive in it worries me a bit. I've always thought it was good stuff for cleaning up dirty engines and injectors, but I sure as heck don't want to be removing material!
That restore stuff sounds plausible enough to work without grinding stuff away. Seems like I've used it before to keep a dying engine going, but can't remember for sure.
I had to pass emmisions once in Colorado, and the car i had blew some nasty numbers. I got a can of some sort of carb cleaner, not the aerosol type. (it may have been berrymans b-12). The can of carb cleaner I slowly poured into the throttle body, which made the ole car spit sputter, and finally blow some nasty oil out of some sort of a tube. I also put some fuel injector cleaner in the tank. I went back for testing that same day and the guy looked at me like I pulled off a miracle when he tested it. He asked me "what'd you do to it??" And after finding out I'd passed, I told him I cleaned out the throttle body.
I've also heard of a guy that passed emmisions after running a tank of gas that had a couple gallons of biodiesel in it.