I'm not so sure of your conclussion on the '05 only having the 2 spider diff.

Both RiNky and I have '05s with 4 spider diffs.

Another fact; I ordered a new rear end for my racer and got an '06 M226. When I opened it up it only had 2 spiders in it and it was a e-locker. This was the rear end I ran at the Parker race. It made 137 race miles and broke the spiders. "So go figure"

So Lloyd, you might only have (2) broken spiders. That is really more like what you discribed as what you heard.