Does anyone know if the motors that come with the metal gears are actually any different than the motors that come stock on a Heng Long Tiger Tank?

Yes, there's no slipper clutch. Not having it increases your torque because the gears will always try to spin, but it also increases your odds of blowing the board if you push it too hard up a difficult hill or with something stuck in the tracks. Also, the metal gears require that you break them in; stock (plastic/nylon) gears do not.

You could glue the slipper clutch to nullify that "feature". In that case the metal gears would be more durable than the plastic ones.

Of course, there is also the increase in weight and gear noise from the metal.

Overall, they're the same gear ratios with the same motors. Just plastic versus metal.

I think it depends on the seller. If the motors are white capped, they are the now standard, low rpm, high torque motors. If they are black capped, they are the older high speed motor. If they're something else, they're not stock or very new production.

Oops...just saw the thread title and completely answered the wrong question. Sorry about that. If you do a search, Swathdiver put together a thread with specs for a bunch of the different motors.