I think that the 3.5mm plugs would be too small. I don't think that they are rated for much current at all.

The wires on the Feigaos that I've seen have the last half inch or so bare and tinned so that you can solder to them. The rest of the motor wires appear to have some sort of varnish on them, which (from what I understand) resist soldering.

As for my little accident, I turned my buggy chassis into a canoe. Other than that, I had to rotate the motor to use the other mounting holes, I had to get a make a new set of standoffs for my servo tray, and bend the servo tray straight. I put the chassis into the oven on 500* for about an hour and then put it into a vice and straightened it. It's running now.