When I rebuilt my 2.5 there were 3 valve cover gaskets in the set, all slightly different, thinking,,, Rubber is best I used it, leaked like a seive. Called the Felpro Tech line and he asked me to describe my Valve cover, turns out there is a valve cover gasket for: Stamped Steel, plastic, Aluminum with and without tabs. Based on the head and valve cover description he gave me the correct part number (Which I have lost arg...) and once I put that one in the leaks were gone....
Good Luck
Dave