spektrum RX^s (orange version) can be had quite cheap. I watch hobbyking, and picked up 12 rx's for like 4 or 5 bucks each a little while ago. each person has their own preffered radio, for the reasons make sense. Is one brand better than the next? yes and no, but its gets even crazier from here. If your inclined to pick up the top teir versions(they all have a upper spec TX) then you also need a super fast servo, special RX (or premium ,to take advantage of the response rate) and after all this money, need a reaction time on par with john force. Are these worth the cost? yes, but i would be honestly suprised if the micro-second reaction (response rates) could be a game changer.
I can say that the super fast servos are worth every penny and can actualy change how you drive, but its a rare need when a servo is worth the cost of the whole car or truck.
If the water proof TX is real, i would get one in a heart beat. Its not because of the name or manufacture, but only because this hobby is year round, and mother nature cant hold me down.
its possible to make any electrical board waterproof, but it would require a group effort, as the coating isnt cheap because you cant buy small amounts. if you want to see the coating, take apart any modern tool or battery. milwaukee, dewalt, makita, AG, etc... they all coat the boards as a protective measure. i wouldnt put my tools in the lake, but the boards would survive.
the tool companies do this to help protect the boards, for drops, hits, abuse,etc.. it adds a tiny bit of strength holding componets down, and keeps dirt/dust from altering power flow. Cool stuff, this comformal coating. (water proof phones have this too)