I went a slightly different route, but used the location above the mirror in my Cobra and Excursion.
The unit came with a box that you can mount, then run a phone line cord from. I mounted the box under the dash, then routed a phone line extension with the female "box" end emblem taped to the very top of the windshield. I also made a very short pigtail of phone line that goes between the V1 and this extension. When I pull the suction cup mount off the windshield, I only need to unplug the little pigtail and leave it connected to the V1. All that remains is an un-noticeable little box.
(I did go a bit further and installed a power top switch (my car's a coupe) and use that as the mute for the V1)
You can buy the phone extensions at Wal-Mart or Radio Shack. The ones I got where white so I sprayed them black so that they are not noticeable.
Here's the V1...
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Here's where the display went in the Cobra.
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