I tried on LOADS of sunglasses, and walked outside in the sun with all of them to carefully observe details (leaves in trees, details in buildings far away, and one particular sign at a chinese resturant across the road that had a lot of detail in it). I was stunned to see the clarity of these Keanens. The 580 glass Costa's were too heavy, as were some of the Maui's - except for the sport's, which i didnt like the frame style) Furthermore, after I bought them, on the drive home it started raining some (thank you sub-tropical storm off the NC coast) and the copper tent was great while even in rain / low light. Thy actually made things brighter and sharper.
These would look AWESOME with your 911
If time and gas count, I spent a grand on these glasses.
BTW, good luck finding a place that sells them.