Nice Excursion dude. Ignore all those haters who apparently dont know alot about the Powerstroke diesel engines. With a few small mods and a proper tune 20mpg is easy. AND............. you can still get nearly the same mpg towing a load! Can't do that with a Prius. LOL!! :beer:
Of course I might be a little biased. Here's my latest addition to the stable:
As far as the window tint question........ Depends on what is legal in your area, how easily you can get it inspected if it is below legal, and whether or not you care if it's legal. LOL!!
20% is a good all around darkness. It's dark enough to give you some privacy without beig so dark you cant see out at night.
Like VisciousJay and Gither said, 20% all around looks nice. They look dark but not so dark that it draws attention and it doesn't hurt that the back window is already 20%.