With my previous Challenger being Pitch Black, and more oriented towards shows than races, I was a big advocate of Collinite #476 and not spending the money to have the car coated.
With my current ride being primarily for racing, and NOT being Pitch Black, I bit the bullet and bought Gyeon Quartz MOHS coating, along with their Booster and applied it myself.
Gotta say, while I have not been able to wash it yet (tomorrow makes the 6th day post-application and you need to wait 7 days before washing) to witness the hydrophobic nature of this product, the little tests I did with a water bottle showed the water running off the panels faster that poop through a goose!