[Savage GT]

I think Maurizio has said in the past, there should be no difference, the motors were all manufactured to the same specifications.
It has been rumoured that the darker ones have the edge from some racers, I don't know if there is truth in that.
The squarer edged ones are newer and also rumoured to be better ...

The bright orange were originally listed as 21k, the ones with the mini pcb are sold now as 23k, but again Mr Slot.it says the specs are the same, it is just they have always been closer to 23k.