How freely a motor spins is directly related to the strength of the magnets used to make it. If it spins freely then the magnets are weak and the motor will be shit. Ergo the Solink feeling clunky as it turns is, in fact, a sign of a better motor. Having changed the motors in a couple of Specna guns I can attest that they are, in fact, weak as shit.
Also, the X-ASR MOSFET is rubbish.
I also very much doubt the X-ASR can deal with a brushless motor. Fuck it off and put a decent unit in instead.