I have a 1990 F-150 with 351w, currently with the M5OD. The synchros are staring to go so it is time to start thinking of beefing up the trans by going to a ZF. The 94+ trucks have the updated internals for 470 ft*lb rating. Does anyone have a good review for the rebuilt units? I am weighing pulling one from a junked truck (typically 125k+ miles) and dropping it in or going with a rebuilt unit.

What do the rebuilders typically replace? My concern is shortcuts during the rebuild and not quite knowing what you get.