@skiinxs This is going to be a really interesting thread I predict! A quick "google" and perusal of resulting threads seems to indicate that the US Gov't has regulated that Zinc additives (ZDDP) not be used in oils for gasoline engines, only diesel and off-road racing. Therefore, it could just be that they cannot any longer get the "S" specification because of this. Probably is the same oil as ever but who knows. Also, I read that the zinc is bad for catalytic converters but some wags say that is only if you are burning a bunch of oil. Again, I can't wait to hear others chime in on this.