Mine is 30% all the way around. I told my guy I wanted it legal, plus I want to be able to see out of it.
From the outside, you really can't make out the person on the inside. It does cut out the heat from the sun tremendously though.
My son has limo tint on his 540 and anytime I get into it I think the rear view mirror is pointed at the back seat. Way too dark for my liking.
Here is my AW with 30%, unfortunately the front windows are down, but the rears are also 30%:
