Okay, I've added splash guards to the truck. The splash guards still don't completely cover the 305 wide tires, but it helps a lot.

http://i93.photobucket.com/albums/l70/MYTTZ06/truck.jpg

Those aren't bad. Who makes them?

I bought the set from the dealership. The rears are molded and designed specifically for the truck. The fronts are semi-molded, and are for a wide variety of applications, but you just have to make them work.