[dpvu]

They are TM compatible for the most part except for the actual gearbox. The split design is quite unique and the lower and upper receivers won't accommodate other gearboxes. The gears are the same except for the bevel/pinion gear (the ICS ones have a bit of a sharper angle) but those can be swapped and only becomes an issue if you're upgrading the motor or gears. Another difference is the anti-reversal latch (it's a different design so the forward assist releases the spring tension).