Window Tint - newb

I just bought a 2003 civic EX which currently has tinted windows (not very dark at all); however, the back window has bubbles and looks horrible because the last owner must have used cheap tint or did it themselves. I'm in the process of taking that off, but my question is: If I want darker tint, do I have to take ALL of the tint off from all of the windows, just to make it a few shades darker? I'm not really sure how it works.

And since i live in PA, the law is technically 70%... what % would you guys go? I definitely want darker than 70%

Since u said the back window tint is bubbling up, I would take off all the old tint on all the windows and get it replaced with the darker tint. I would get 20% tint. I have 20% tint on all of my windows except windshield and I've never been pulled over. Where I live the law is 50% front and 35% back. 20% tint is dark but u can still see inside the car or if u wanna stay clear from the cops I would get 35% tint. 35% tint is almost clear but u can still kinda tell there is window tint on the windows.

i got 17% all around my car and 35 on the windshield i wud go with 17 u can barely see in it but ive never been pulled over in my life. at night its sweet as shit. im completly invisible inside from the front wind to the sides =]

i would reccommend Llumar for any automotive window tinting job we use it on all our cars look at the qaulity of the window film. No bubbles or pealing
(Link removed by moderator)

I agree with the others on here. You should completely remove the old tint and replace it with new ones. I recommend going with an installer and company who prides in the UV rejection rate and the quality. I just used them for my civic as well. This link will provide all the necessary information you need http://detailwiz.com/car-window-tinting

It's all about luck really. Some states and/or law enforcers will let you slide by with dark tint, others will give you a ticket. I know what you mean, tint only looks really good when it is really dark.