x2 - compression ratio and oil pressure have nothing to do with leaking at the oil pan. The pan is not pressurized, it only sees crankcase pressure.

Speaking of crankcase pressure, how is your PCV system working? Catch-cans hooked up in any configuration different from stock? PCV valve working OK?

Depending on year/version, there's little steel spacer rings around each bolt/stud for the oilpan. Did you leave one on, so now there's 2 of them stacked on the same bolt??