i had a 46 tooth plastic on mine for a while, the holes need to be reamed a little to match up the bolt pattern , i had to just take my time and be sure the holes lined up as to not strip out the mounting screw holes, i didnt have any leaks either
ill try to get a pic up later, the spacing is about 1-2 mm to narrow to fit perfect, so i reamed the holes with a body reamer in the direction i needed the screw hole to go, i think i had to go straight out towards the teeth with all four of the mounting holes
I would imagine that could also leave room for diff fluid to leak out. Why not just get Mike's hardened pinions and use stock spur? Unless you are concerned about noise everyone here (including me) has been having great success with the hardened pinions.
I have mine on XB8EC and no wear problems at all.
“Everyone has a right to be stupid; some people just abuse the privilege.”