First of all: This is NOT a thread asking whether or not I should go to synthetic... I've seen too many.
My 2003 5vz-fe is going on 150,000 miles and I'm thinking about switching to synthetic after I get through my list of maintenance projects. Most important to mention, since it relates to oil leaks, replacing the valve cover gaskets, cam plugs, and changing the gasket on the semicircular plugs.
So for those of you that made the switch and complain about leaks... what leaked and how hard/expensive was it to fix? I want to know what I need to look out for and the POTENTIAL risk. I'll be going synthetic all around - engine, tranny, diffs, transfer case.