They are excellent stock, and the diffs in them hold up well compared to the first MLST. I've run 11.1v lipo on a nasty Wraith 7k and never popped a F/R diff.
The weak spot on the stock truck is the center diff, it gives all the power to the front wheels on take off, prevents wheelies and is the first thing to let go. Either use a spool to lock it or a MIP center ball diff to control the power delivery, the spool will give you proper monster truck action and the ball diff will allow you to pin the throttle without drama (provided you set it up properly).
They are very robust with the exception of the steering system, the servos tend to let go, though are very powerful as stock, and they have centering issues. These can be solved either by swapping out the servos for JR or Hitec (modifications required) or you can improve the steering setup with alloy parts and an adjustable turnbuckle link rod to take the slop out of the system.
At the end of the day, you can leave it totally stock and it'll never crap out on you unless you really tear it up. Or, you can pimp it to the point of ridiculousness. The parts are more than available.
