No rebuild kits that I am aware of, but I still have to take my spare turbo to a local shop and have them check on something for me - The center cartridge seems to want to rotate on the compressor side, which would mean bad things for the VNT servo.

Try to visualize this - The outer body of both snails is held to the discs of the center cartridge with a bunch of bolts around the edge. This allows you to "clock" the snails for best fit in the engine. The vacuum servo bolts to the compressor snail, not the center disc.

Normally, the center discs are fixed in place - how, I'm not sure. Internally somehow. On mine however, the disc on the compressor side moves when you try to rotate the compressor snail in relation to the rest of the turbo. The disc is solidly bolted to the snail, and the turbine shaft has no play, spins freely and smoothly. But with this disc being able to rotate, there is a good chance for damage somehow. So I can't use or sell this until I get it checked out.