I saw this and based on the hype I've seen, I bought a couple of cans when I saw it at a local AZ. I actually tried it. I guess I didn't use it right as I didn't go for a drive after using it. The engine looks OK. However, I'm extremely leary of spraying some chemical on a part and that's it. I'm uber-anal when it comes to engines...
Polished each Bosch sensor to a mirror finish with a Dremel.
My expectations were low and they were met. I think CD2 is a good engine dressing for a new engine with those big plastic covers but for an engine that's seen some serious use, it's just not going to remove the years.