If you're going in you should change the timing chain and tensioner, the cam gear and dist. drive gear, the tensioning rail , upper and lower guide rails. You'll need to pull the oil pan so you will need a new oil pan gasket. You should also repace the front main seal. There is a real possibility of tearing the cylinder head gasket so mercedes offers a replacement section as a repair, the part # 102 016 05 80. There is also an o-ring for the oil pump to block connection, 006 997 40 48. I thought there was an oring for the coolant passage through the timing cover but could not find it in the EPC, maybe someone that's had the front cover off one recently can chime in on that one.