$270.00 for a sunshade!

Wow, no wonder dealerships are called
stealerships sometimes. Mid America has a sunshade for $79.99. You can find it
here. I've got one for my car and it is great. It takes all of 30 seconds to install or remove the shade, and it folds up nice and small.
I would recommend taking your car to a shop that specalizes in tinting windows. They will be able to answer any questions you have. The limit in Washington state is 35%.
Tint was the first thing I did to my '08. The guy that owns the shop I went to owns a couple Corvettes. We got to talking and he gave me quite the crash course on window tint.
If you look at the back window, you'll notice there are a lot of small dots on the window. Who ever you get to do the window, make sure they do not try to put tint over those dots. The dots are slightly raised, and they will prevent the tint from sticking to the glass properly and eventually you'll get a lot of small bubbles in your tint.
What happened with my car was that they put the tint on the rear window, except over the dots. I waited a few weeks to make sure the tint had set properly, then I went back and they masked off the window and painted over the dots. All in all, they did a really good job, and it all cost less than $200.00.
Jason