5%!!! Way too dark for me. Your front windows look to be lighter then your back in some pics. I've got 20% and it seems perfect for the sunny days but not terrible at night. Many years ago I had a car with 5% on the back window and I hated it. I had that taken off and had 15% installed and it was much better. Legal limit in Washington is 24% but I've got several cars with 20% installed and I haven't had any issues with the police.
I did have a 5% strip done on the top of the windshield though.