Brian, check
www.filairsoft.com. I recall reading a thread in their forum about these gears and setting the auto-shim. I also recall someone saying the little springs tend to give out and the auto-shim goes out of alignment after about 100,000 rounds or so. At this time, Phoenix offers no replacement springs.
*edit*
I can't find the exact thread and I have to run, but here's what i got:
Phoenix:
+ Strong material, nicely finished (but not extensively tested by me)
+ auto-shim system
- auto-shim system has some problems on bevel gear (washer may get stuck after short time)
- expensive, only good priced on ultra torque ratio