Yes, clutch pack diffs do get worn down quick with elevated power levels [or shoddy design]. In your examples, it's likely the owners aren't fitting appropriately sized clutch packs per their power level, especially if the stock item is barely good enough for stock power. It's all about having the right size hammer for the job
Good to hear the ZR1 diff is up to the task.
Long story short, the factory Torsen in the AS1 will be a great solution for virtually everyone. I'll be happy with it as the car will be my daily driver. No maintenance, quiet, easy.