First of all you don't need to spend that much. There are others out there that are significantly cheaper and very highly regarded.
Second, all Ram Mounts are vibration damped. It's inherent to the design.
The air flow behind the screen is one of a couple of important parts of eliminating buffeting. The height of the screen, distance of the top of the screen to the riders head, and airflow under the screen are all important.
With a Vee or Wee 2004 to 2011 an awful lot can be accomplished by putting a 1/2 spacer (e.g., stack of washers) under the lower two windshield carrier mounting bolts. This also provides enough airflow that mounting the GPS above the screen has no detrimental effect. A Madstad bracket does much the same for a lot more money.
A Givi Airflow windscreen (AF260 in your case) is probably the best solution and is compatible with all above dash GPS mounts out there that I'm aware of.
There is a relevant thread here. http://vsari.com/index.php?topic=576...icseen#msg5367