Some Guns come with the wires soldered to the motor terminal like my Ak. I see nothing wrong with wires soldered to the motor terminal those motor connectors sound expensive for 50 cents a piece compared to solder you can use for a long while. De soldering and soldering does not take a long time with the proper equipment. As for TM wires I don't think TM makes wires the distance from the battery and the motor is very short and will have enough resistance to cause noticeable voltage drop.
In short learn to solder it isn't that difficult and it's a handy skill to have.
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