I did mine on saturday to lay some rca cables down the centre of the car.
I had to remove two black rubber bungs from under the car which then exposed the two nuts holding on one runner. Using the slightly longer socket from my socket set, I managed to get them undone.
There are two more in the center of the car along where the exhaust runs. There was a bit cut out of the metal on mine so that you could get to them.
You might be able to remove the seat via other methods, but if you dont take the runners off, you cant lift the carpet up