Mine is also 20% and it matches almost perfect........ i do noticed lookin out from the inside its a little different....... but the outside it is not noticeable...

 

Mine looks like the one above FWIW.(20%)

Most of the time it looks like the factory,if you catch it in the right light/angle it's a tad off, but good enuf for me.

Since most everything i've driven recently has had window tint,when i first got the SS i thought i was gonna burn to a crisp w/ no tint LOL.Plus it looked so wrong with just the front windows not tinted compared to the rest of them,so it made sense to get the fronts done too.

And it DOES keep the inside much cooler too.

My '03 Silverado was tinted w/ one shade darker than legal for Indiana, but over the years i think it has faded a lil so it's not as dark as it used to be. 5-6yrs/200K miles-1 police stop(speeding ) and no issues with illegal tint ,so i'm lucky(?) or something.

Also had a '84 T-bird long ago w/ damn near limo tint all around(bought it used that way),and somehow got away with that
(That time is WAS luck )

 

I've had 30% film tint on my fronts and 15% film on my rear windows since I've had the HHR. I need to take it back in to the tint shop to get the passenger window redone since someone decided to break through it, so I'm thinking about going darker in the back while I'm at it. (25% is the limit for fronts in Texas so 30% is as close as I've found, and my safety inspection comes up in 3 months so I don't want to deal with failing that over window tint - otherwise I'd love to match the front and rear.)

I didn't realize the factory tint was 20% in the rear until I saw this thread, and I'm actually really surprised it was that high, it didn't seem that dark. As it is, 100 x .2 x .15 = 3, so technically I'm at 3% light transmittance in the back, but it really doesn't seem that dark. If I went with 5% film in the rear, it would be 100 x .2 x .05 = 1.

Now 1% transmittance seems a bit extreme. Has anyone done their aftermarket tint this way? How'd it work out? As far as legality, Texas doesn't regulate anything but the front windows and windshield, so that's not an issue.

 

AL tint limit is 32%...not that 3% makes that much of a difference, but notice it applies to all windows except the windshield where you can't have any:

"Section 32-5C-2
Prohibitions against operation of motor vehicle under conditions which reduce light transmission.
Except as provided in this chapter, a person shall not operate a motor vehicle registered in this state under either of the following conditions:

(1) With material or glazing applied or affixed to the front windshield which reduces light transmission through the front windshield.

(2) With material or glazing applied or affixed to the rear windshield or the side or door windows which reduce light transmission through the rear windshield or side windows to less than 32 percent or increase light reflectance to more than 20 percent, with a measurement tolerance of at least 3 percent. The light transmission shall be measured with a device or instrument capable of measuring light transmission before a person may be charged with a violation of this section, and the officer shall be equipped with such a meter before stopping the driver.

(Acts 1996, No. 96-534, p. 746, §2.)"
http://www.legislature.state.al.us/C...975/coatoc.htm