"...and i remember, one time i spilled a few drops on the driveway. then lit with the lighter. get this, there was a bunch of smoke. so i wonder......"
Versus? Think about it. If it was really flammable dont you think it would either quickly food the engine or worse, detonate!
A lot of people say it works well. I've been happy with it. Just remember, the engine needs to be up to full temp. If its cold it wont do crap, it needs the heat. It is not a cleaner to use with a brush.
Put it in a hot engine and as the can runs out you stall it out. Let it sit for 20 minutes or so and start it back up. Take it out on teh highway to help blow everything through.
If anyone comes across before and after pics that would be cool though, would be nice to know for sure it works and how well.