The one thing to note is that this one you have linked here is made for desktop use. From the looks of it you would have to highly modify the base to get any stablity out of it in the bumpy environment of a car.
The high price stuff is Jotto Desk or a full setup from RAM Mounts. Also Panavise as some very nice options, some of them made just for your car model.
I decided to go half and half. Used a dual ball joint mount from RAM Mounts and fabricated my own base bolted into the car body. The mount was $25 from GPS City and the fabricated base was $15 of scrap aluminum and a weekend of work. One important thing to note is that the longer the arm of your mount the more support it will need to keep solid and not bounce around. Mine is only 10" long and it keeps pretty solid with 4 four 1/4" bolts.