IIRC Deans plugs come in brass, and nickel plated. They are of a good gauge and should suffice for the draw of air soft motors. I used standard Deans plugs on a helicopter that had like 20amp draw with a brushless motor setup..worked fine.
It's not just about the ability to handle the current, even the almighty Deans (which I highly recommend for all intents and purposes) do introduce SOME resistance. Granted it's only about 1/10 of what tamiya's have, it's still about the same as several extra feet of wire. Direct wire isn't the safest without a gun-side cutoff (which introduces enough resistance to negate the benefits of direct wiring, unless you use a solid state switch (such as a mosfet) to control the safety portion of the current, in which case your wiring will be pretty complicated and it's still not a guaranteed safety solution), but it does have remarkably low resistance.
Just so everyone is clear. My guns run Deans connectors, not direct wiring.