Looks like a bit of a waiting list for a Magnum XL at the moment, Hope to get some more info next week. Talked to the Shop where I take my Boss (ford will not help out on warranty since I did a direct import to Chile) and the shop owner offered to get me the box rebuilt, he was a little surprised to hear the idea of a swap and he does do the Shelbys here in Chile. Will get a quote for a complete rebuild with new bearings and syncros before going the Tremec route, though it still sounds the best route. Maybe try to get better quality parts etc with the MGW shifter........