stay away from metal spurs. the spur is plastic so you have a weak point that is easy to get to. metal spurs won't strip but you WILL kill tranny gears and that a lot harder to get at to replace. find out why the plastic spur stripped and fix that problem. make sure the engine is tight, the tranny is tight, and your gear mesh is set right, and that the slipper clutch is set right
stay away from anything Integy, its crap. run rpm arms.
rule of thumb is "aluminum donw the center, plastic on the corners"