I have an engine builder and also a master tech friend that swear by this stuff. Anyone here use it? My friend said his chevy 2500 w/ a bbc was burning a quart of oil every 1000 miles quit when he started using it. He also said that the oil will last about twice as long when added. My engine builder said all other additives he has seen are bs but this stuff is good and definitely reduces friction. I bought a quart at cost and I am going give it a shot.