The XQ-Power S4020D I talked about previously has case seals for splash/water protection. Smear over the case seams with plasti-dip for extra protection, and you'll be set.
That said, my two Savox 1256TG's (E-Maxx and E-Muggy) also have silicone seals for the case, and will be proof to most water (outside sending it swimming!)
Just checked, the 1258TG in my LX2E also has case seals.
I ran my Muggy and Maxx in the snow all winter, without plasti-dip, just the stock case seals. Never had an issue.