Holmes BRXL is awesome.... Takin FXR is nice ... But more expensive.. With motor will be over $1,000 ...(brushed)
17.5 brushless is pretty good for SCX10, it isn't a comp crawler ... You may not want it super slow, just that brushless sensoreed system don't like water ...
500-600 castle creation sidewinder will be the best buy, waterproof, smooth and good drag brake. brushed and sensors brushless.
Or raise the budget to get holmes hobbies BR-XL, very smooth and great drag brake, 6V 5A BEC! brushed only, I was using castle and switched to BRXL now.