Here is a site that will answer any questions that you might have.....
www.rightchannelradios.com
I plan to route a heavy gauged ground wire down to the body/frame. That is what I ment about having the wires hanging. If I didn't have the top of my cab Line-X'ed to the windshield then I would be opting for the Wilson 5000 magnetic mount. The magnetic mount grounds itself thru the magnet to the body & will not work in my case. I understand that the magnet mount works just as well, without the mounting headaches. The key is to get it as high on the van as possible but you can get antennas that will give you the extra length to clear your penthouse if that is a concern. Wilson comes with a 8 or 10 inch stem at the base, giving you the extra length. Give the website a looking over & you'll see that it has every application out there. Grounded, Non-grounded, ETC
Good Luck Woot............