1. That really depends on how strict your police are. I've been darker than legal for almost 10 years and have never had an issue. I doubt they will pull you over for it but could tack on a ticket if they have you stopped already.
2. once again I have had tint on for almost 10 years and never had an issue with the defrost or the tint getting damaged.
'14 Tuxedo Black ST3
'13 Ingot Silver Escape Titanium AWD
'04 CD Silver SVT, #877, 1 of 135 May 2011 ROTM, FF11: Best Display, Best of Show; AFN12: Best SVT, Best Audio, Finest Five, Carlisle Nifty Fifty