OK, the last post trigged my memory. Mine were done at 15% to visually match the rear from the outside, something about the way the film looks versus the original glass.

Be aware that the color does not match from inside and that it does make it difficult to see in the dark or in inclement weather. I'm a pretty attentive driver but if you don't really pay attention in less than full sunlight conditions you will get yourself in trouble with this level of tint.

Honestly, I'm not sure that it's a great idea to have them so dark but it does help allot with the heat and glare here in SoCal so I'll probably keep them for now.