So this weekend I switched to 500k in the CD and roached my first spur. I'm now wondering if it might be too much for it when running gear difs. However I very carefully replaced the spur and rebuilt the dif and it lasted through the race program and a practice beforehand today with no issues. I'm going to keep running 500 and see what happens. One thing to note is that when replacing the spur you'll want to be careful not to tighten the screws down too far as they can actually push up on the area where the two halfs of the dif meet and can cause leakage or worse break the case. Just be cautious.