Hi philipat,

1) PzIII sound version is only availiabel on TK22 platform,
2) "rotate the turret, raise/lower the bbl and fire the machine gun at the same time while driving" this can not be done becasue TK22 is 4-CH operating board.
3) Only TK22 has gun barrel elevation servo port, you just need to plug a servo to it.
4) Only TK22 has "momentum" feature.
5) both TK20 & TK22 support airsoft with sound trigger.

TK22/20 are 4-CH operating board, no separate switch for something like starting the engine or firing the machine gun.

Regards,
Clark