I don't recommend a steel spur, if you are stripping spurs during break in it sounds as if you do not have the mesh set correctly. If you run a steel spur you will chew up clutchbells too, especially if the mesh is not correct. Then you also run the risk of damaging tranny gears, as .21rc10gt mentioned, using a plastic spur gives you an easy to repair, inexpensive weak link, and with a properly set mesh should last a good while.