I'm always surprised that Kenwood doesn't give more technical information on their web site. Both Icom and Yaesu post all of the specs including the size of the parts.
I don't know the EXACT size, but it is too tall to fit the Accord sun glass holder. It is ABOUT 6 inches by 4 1/2 inches.
A better place is on one side of the center console. You want to keep it as far from the air bags as you can. The one drawback to the Kenwood, is the mic is plugged into the main unit, not the head as the aforementioned ones do. This fact raises an RFI issue depending on what you use to extend the cable, and how long it is.
If I had to recommend a radio, it would be an all band one, not just VHF/UHF.