My E46 had the Moto V50. It is a standard phone but with BMW specific Firmware to enable it to work correctly with the car kit equipment. I bought a replacement V50 as the one supplied looked like it had been used for football practice but it wouldn't work properly with (if I recall) the steering wheel controls.

I swapped the cases over in the end to get a tidy phone.

Yes, it does take standard small SIM cards and if unlocked (which all the BMW supplied phones are) will work on any standard GSM network.

As far as I know, the eject box will only fit a V50 and none of the others.