Valve cover gaskets take about 2 hours to do properly. Remove engine cover, all coil assemblies, disconnect fuel line at fuel rail, remove breather hoses from valve covers, remove complete valve covers, remove breather covers from valve covers, clean nasty old black sealant (the most time consuming part of the job), clean mating surfaces for valve covers at cylinder head, apply new sealant to breather covers and reinstall breather covers, place new valve cover gaskets on valve covers, re-install everything in reverse order. I believe the spec for valve cover torque is 9Nm (this is what I do at least). The only thing I would be sure to have is a good applicator for the sealant. M-B recommends between a 1 and 2mm bead.