I'm not sure what you guys are doing to your diffs, but, I sand the rings and use ceramic diff balls and I'm good for at least 4 race weekends. If I'm feeling lazy, I wont work on the diff for 6-8.

Back in the day when I ran an RC10GT (and the parts were supposedly better!) I had a diff that would get gritty after 1 tank of gas. No matter how carefully I rebuilt it, it would not stay true. After several attempts I realized the outdrives were bad. I ended up buying a complete diff and that fixed it.

Unless there is something wrong, an AE ball diff should and will last longer than most.