Sorry, couldn't find my part numbers, but here's a link to the towers; the Yak Lowrider is the lowest tower I've found.
http://www.yakima.com/Product.aspx?id=144
Buy a set of four towers. The towers are very easy to install and fit right in the stock placements on our factory rails. Simply pop off the four covers on the factor rails and hand tighten the towers into position. You'll notice that the "hook" on the towers fits right into the rail indents. Very sweet.
You'll also need two Yak cross bars. 48" is the shortest Yak makes and don't overhang the VX too badly (the standard Yak cross bars are round vs the oval cross-bars that came with the factory rack). You could trim these down (shorten) with a hacksaw if you wanted, but I think they look OK.
I'd also recommend you pick-up a Yak SKS four-lock set and put a lock on each tower. Around here, if your rack isn't locked on, its gone. Maybe a six or eight-lock set if you plan on adding accessories (I needed two more; one each for the ski carriers on each cross-bar).
Finally, take a 10-minute drive on any bumpy street road and then re-tighten the towers by hand; you'd be amazed at how much more you can tighten them (I got two full turns).
Best,