Did my first 300 mile trip with the Legacy Wagon, and the used MAF sensor seems to be working fine! Also put the new valve cover gaskets in and checked out the O2 sensor. Discovered a oil leak and believe that it is leaking from the oil pump. Besides the leak will get around to fixing the rear muffler, the bottom is rotted away. Found that a SG-36 universal O2 sensor should work in the Subies. Steven.