As the subject says, how difficult are they to do? I read in other forums (Audizine, Audiforums), that the oil pan gasket can either be the top or the bottom one. I think it is the bottom one. The oil change tech told me that it is leaking, and also my rear main seal is leaking as well. Engine is a 2.8 30 Valve AHA. Danton J.A. Cardoso