The G80 locker is great for it's design purpose, and usually gives good life in normal trucks.
Here's what it's supposed to do:
If you going low speed or stopped, and one tire starts to spin faster than the other, a little pawl engages it and it locks solid. It unlocks when your speed gets up to ~20mph. The pawl mechanism is not built very strong, and sudden engagement on asphault can bend it. For racing, you want engagement at all speeds where tire slip can occur, not just low speed. And when one tire suddenly grips on asphault, you need it to give some.
For racing a limited slip or a Torsen style will survive better. My favorite is a Torsen style, which is a high bias geared unit with no clutch to wear out. A limited slip uses a clutch, and it eventually wears out.
The Dodge version of the AAM comes with a limited slip or Torsen, don't remember which. Several guys have switched over. I have a Torsen style sitting here that I'm going to use in Casper.