I would say maybe, but probably not. I've opened the cases to waterproof mine, and theres no input to the card for a separate receiver. We're lucky they give us an optional output!
I would say it's worth it to get a new ESC if you're wanting to use a different radio set, the stock ESC has poor throttle modulation and produces excessive heat in the motor IMO. I'll keep preaching the wonderful drivability of the Furitek Lizard/Iguana units, they'll power a brushed motor no problem, and would be a direct plug in setup with your rx/motor. Theres also cheaper ESC units on Banggood and the like, but I can't speak to their quality at this time.