my mechanic tells me that my new 90XJS v12 with 37 k has aleak at the head gasket;in addition the diff needs rebuilding;he is quoting me an "engine out" repair at about 40-50 hours??? sound right? i paid $8K and it is immaculate but this did not show up on my pre-purch inspection; took him 2 weeks to run it down; i hate to spend about$5k on these 2 items..any ideas on labor or anyone else in Atlanta I can check with? thnx, Dogdoc