Safariland Solis holster fits fantastic. Should also fit a C1 or X1 also (it will fit a 48). Accommodates any of the three lights that will fit a micro or 43x MOS ( TLR7Sub, Nightstick, or Surefire). Also accommodates optics (I tested with an EPS Carry).
I have tested transplanting a 43x trigger group into the Micro, which fit perfectly. The 43x in the micro have some differences to the trigger group internals, so I you can't swap individual parts like the trigger bar or return springs, but the whole group is swappable.
43x/48. Slide stops will fit. They are different than the factory micro slide stop, but the micro frame is cut to accommodate either type. I tested this to confirm.
The rear of the micro slide has less taper at the top, so any Glock sites should fit fine. I installed a set of TruGlo night sights for a Glock 20 on mine, and they fit perfect.
The threaded 43 barrels from aim Surplus they were blowing out for 29 bucks as blems, also fit and work fine.
A shield arms mag release fits and functions. Gen 3 Shield arms mags ran fine for me. Gens one and two did not.
Probably some more stuff I'll think of in a bit.
Oh, Safariland 7378 holster for a 43x fit, but fit tight. It was serviceable though.
A Safariland 7371 for a 43x did not fit, but it won't fit my 43x MOS either.