i used it on race and street pistons that had it on them i feel a top coat under side of piston may help more on the street then the grafal skirts if you do not prep your bores good its all off very fast i feel the mahle is a good piston for making power but not a piston i would use in a every day street van with it contact reduction skirts .i seen it on many stock pistons for every day use but most all the times. i have taking them out or seen them used its off . i can get the mahle /pbm with out the coatings