I have a buddy that re-built his own honda civic and swears by seafoam. Hes had lots of friends that have used it and claim that, "When used properly it increases engine reponse and power by 50%."

But ive heard horror stories. In some cases the carbon crap thats in the engine covers bad seals. If you take it off the bad seals are once again exposed and not designed to handle the pressure or oil of the engine and start major leaks or engine damage.

I've never seen this first hand, only hear say. I've heard more good than bad and I'm considering trying this seafoam myself , i just have no experience with the chemical and what it does or how to use it properly.

Does anyone have first hand experience actually using the stuff?