[MetalMan]

The 8s won't necessarily have more torque, since it has to do with the number of amps the motors will pull. Unfortunately, Feigao doesn't publish the kt ratings (torque constants) for their motors, so we can't tell which motor will put out the most torque at the same number of amps.
It's relatively tough to decide without actual numbers which motor has the highest kt. The 380C 6L is longer, but the 540 8s is larger in diameter. They have similar kv ratings (by several hundred). If it were my decision, I would pick the 380C 6L. The can of this motor is a heatsink, so it can dissiapate heat well, and it has removable endbells that won't pop off like the 8s's endbells will. This also makes motor maintenance (bearing maintenance) easier. Besides those things, the 380C 6L is less expensive.