I'm in CT (kind of like Chicago weather), and I wanted my EX to look Factory stock. All SUVs come Factory with 20% Tint on rear passenger windows back. I had toyed with 35% all around (except windshield), but decided on the Factory stock look instead. Paid $150 out the door, tax included. Here's a good link:
http://www.tintcenter.com/articles/bt_shops.html
Installer used Johnson (manufacturer brand). Whatever you do, do NOT get metallic tint. It messes with your radio and you will wind up with some static.
Good luck.