Just remember the rear windows are 'smoked tinted' and provide absolutely NO UV protection.
If you live in the west - UV protection is a must. Heck I guess anywhere. But when it's 120 degrees outside - it's nice to not have that heat transfer through glass.
Really wanting to do my front window too. When I had 20% put on all around - the guy said he could do my front at 80% - and I would no longer have to use a sun visor when I park it. For an extra $100.. I wish I had done it. I still may do it.
Also, I feel, at least out here in Arizona, cops understand you want dark tint to keep things cool. If you're not driving around like a bat out of hell everywhere, spinning tires and switching lanes very 10 feet... I don't see you having any issues.
I've had my dark tint for years on my trucks and never been pulled over.