There is one issue with using the revised valve cover on the earlier LS engines, such as the lq4. (I have one in a 2003 Hummer) Almost immediately started getting condensation in the bottom of the oil pan. The revised valve cover has a very small orifice. Tiny compared to the early style with the actual PCV valve. I doubled the size of the orifice, reinstalled the valve cover, and no more condensation. If you have adequate vacuum in the crankcase, you should be able to lift your dipstick up slightly and hear the idle change. Or the oil filter cap. That had no effect prior to enlarging the orifice. And even with the larger orifice, no oil consumption between oil changes at all. It doesn't affect the idle, as the ECM compensates.