it doesn't matter if your windows in the back are tinted, only the drivers and the passengers. That's why you see a lot of factory cars with all windows tinted except the drivers and pass. (front 2)

 

pros:
- less uv damage while you are driving and the window/s are up
- lower cabin temp (pitty you can tint the windscreen)
- more privacy
- looks good

cons:
- may attract unwanted cop attention (if darker than legal)
- harder to see at night
- may fade/bubble with bad quality film and bodgy fitting

go with a well established business/brand, and check if they offer lifetime warranty. i have 20% all round and took them less than 20 mins to do

 

I would add that if you are stopped at night. be sure to turn on the interior dome lights (in addition to rolling down your window)- the officer will then be able to see into you car from all windows (unless you have a limo tint).

I live in an area that stays in the 90s during the summer and my 8 is black on black leather - so it is worth the $135 I paid. Oh and it does look cool

 

can the tint be removed from the back window, in case there is a problem with the Navi?
sorry I have no experience with window tinting and I have the nav...

 

Yes you can remove the tint. I recommend it, I can't stand seeing 8's without it, I feel like it's missing something. You can get it taken off, but I definitely recommend finding a place that someone recommended to you for tint. I went to a guy who was really good, paid $150 for the entire thing, and I'm extremely happy with it. And go ahead, do the front windows even if it is against the law. I just roll down my windows when I pass cops. My roommate got pulled over for tint on the front windows once, and he was given a ticket that stated that if he didn't have it removed, he'd have to pay a fine. He found a friend who was a cop, had him sign off on it saying it had been removed, then didn't have to pay the fine.

HOWEVER, make sure you're not drinking and driving. Cops will definitely use that as an excuse to pull you over, and then you're screwed.

 

even for tinting, damn dealers here ask 180euros, both a Llumar and a 3M dealer...
but thanks man, anyway...