My Boxster has a medium tint on the side windows. I like the look and it keeps the glare down. No problems at night. Most people don't even notice it.
In this pic, the windows look a lot darker then they really are because of the sun angle and the black interior.
I'll try and take another pic over the weekend that is more representative (would do it now but my son has the Boxster this afternoon because I am in the middle of replacing the top on the Miata).