about over torquing the valve cover bolts - once a rubber type valve cover gasket gets squished out of shape, it will probably cause more leaking, so over torquing is not always good - maybe for cork gaskets. some mechanics i know swear by using permatex "right stuff" gasket maker in place of a gasket ("guaranteed not to leak"). MB also sells a black sealer but i am not sure if it is used in place of a gasket...
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"