Ive read that the quality on Comp valve springs is open to question -

Anyone confirm a premature loss of pressure with new Comp double springs?

You may want to post that one in the racing section. I haven't used the comp valve springs so I have no first hand experiance. My machinest says he usually installs the valve springs with a bit more pressure (shorter install height) because the springs will loose some seat pressure after the first few runs?

If the cam is fairly mild I don't think it is that big a deal, but with a big solid or roller it could make a difference.