Here is an alternate method for hardwiring a Valentine radar detector.
I simply removed the plastic piece (only the section that pivots) which is between the two sun visors. I simply tie-wrapped it along with some velcro.
The advatages are that you virtually do not see any cord, the radar will not get in the way of a sun shade (that you may use) , no suction cups, and it is nearly invisible from the outside looking in if you have a strip of tint.
Here are some pictures. If you have any question, feel free to email me.