<<Actually it's real easy to over tighten, so if it's designed not to, it's a bad design. If you tighten until they stop (please define this) I'll bet it'll leak.>>
I've never had a problem with a 16V valve cover gasket leaking (unless it was old). I tighten down the valve cover bolts with light pressure until they stop. The reason they stop is that the cover itself has little "bumps" at each bolt hole, which prevents you from over-compressing the gasket. But the gasket should squeeze out a little bit. I haven't had a probelm in 5 years of doing it that way.
