I will absolutely have them in every car I own from now on.
I am 6'6" tall and very few vehicles fit me. I bought the Leaf, and it was merely "OK" like every other vehicle I've owned. Then I heard about "extend my seat".com. At that moment, they were in pre-order for the Leaf and I clicked yes immediately. A few weeks later the extension brackets showed up. They were easy to install, taking only a few minutes. What an immediate difference!! I moved the seat back all the way, as is my habit in every vehicle, and it was much too far. I moved the seat forward to the point that "Felt good" and drove. I've had the rails a couple of months now and I absolutely love them. They make the Leaf my favorite car to drive.
Also, my wife found a great use for the extended rails that we didn't foresee: When eating in the car (yah, we try not to do that, but it happens), set the rails all the way back and the driver has room to eat! Absolutely great.
Returning to my daily drive of the car, the extenders have changed everything for me. I will absolutely have them in every car I own from now on.