Well, I don't have their kit in hand, but based on my homebrew setup currently (2.5" ducts from the fangs using Modshack's connection method, just dumping into the wheel well area), my guesses are:
(1) You probably do want to paint the front fang tubes. It's easy to do, just shoot them with flat black spraypaint meant for bbq grills before installation, so they're not shiny when you see them end-on (although you have to be pretty short to notice anyways).
(2) For oil cooler kits in front of the radiator, it should be a non-issue. Worst case you do a little messing around with hose routing. For the ones mounted off on the side in front of the wheel well... not sure tbh. It seems like you'd still be able to route this though, as it doesn't come through the *front* of the wheel well. Might just be a little tight in one spot?
(3) I don't think there's any concern about water, so long as you don't jam a garden hose into the fangs. It's a long and convoluted path, and what little gets through it would just vaporize on the brake side IMHO. Keep in mind your rotors are always getting wet in the rain anways, the outside is completely exposed through the wheel
