Depends on cam lift and usage. The OEM style rocker gear has high side loads, and can be a pain to get oiling to the tips of the push rods. I generally have to replace the titanium lash caps each year. The guys running the Barton set-ups run more lift and rpm than I do with few issues. My cam is .780" lift with lots of spring pressure and I street it. If my heads could run them, I would.Stage V is really good, but I think the benifits from the newer design becomes a must at a certain point.