I have been seeing some X's on the forum with a Spare Tire Carrier on the rear hatch. How do these hook up? Can anyone show pics of their installation and what did it cost? I would like to get a Pro-4X Spare rim installed on the rear of my S since my factory spare tire is is too small if I get a flat now. Would like a reliable backup plus it also adds to the cool factor of having one on the rear hatch. Thanks!