Traxxas Waterproof or Not

My EVX-2 has the cutout problems with fresh batts so I am going to send it in and this is traxxas response:

If there was moisture involved in the failure or if the original connectors are not attached, the repair will be $40.00 plus $5.00 shipping. If no moisture was present and the original connectors are attached, the repair will be $15.00 plus $5.00 shipping.

I thought the esc are waterproof ? If mostiure gets in isnt that a function design failure issue? Any way as luck would have it I don't have the orginal connectors on it so I am looking at the Novak Super Duty XR High-Voltage Esc (89.00)to run my kershaw 700 motors do you guys think this would work better and cooler than the evx-2 since its rated alot better in specs....can I dip in plasti-dip with just heatsink exposed and make the Novak SD as waterproof as the evx-2 ?