Mine have never been to the track and just runs street tires (no drags) and mine stripped the ring/pinion.
I do have the 185 pulley and a EC tune but thought I was fairly safe without ever running really sticky tires....wrong.
I found a used diff and bought the WaveTrac package from Rob and it is now in transit back to me. Seemed like the best possible option at this point.
Since it has to come out anyway now is the time to upgrade and then wait and see what the next weak link is and when it breaks ...