Makes brake rotor changes a breeze i see. I'll assume the spring perches just need to be moved?
The '99-04 axles have 37-1/2" spring pad centers where the square bodies are 32". The diff is offset really far to the driver's side and the perch is machined into the differential casting on that side as well, there really isn't a reasonable way to make those work with leaves.
The '05+ axles are all setup for radius arms/coils, I think you'd find the same problem if you tried to retrofit leaves onto one of those axles as well.
