Install 2
Two other things...
The antenna goes from the center of the top trunk (so the tail is 1/4 inch from the edge), goes under the lid to the DRIVER side, goes down the hinge assembly, then goes back along the front weather stripping to (through) the passenger tail light assembly to the Sirius unit (thought that was strange until I did it). You should have plenty of antenna wire left, and they want you to put it in a loop (no larger than 5" around). They say you may damage the cable otherwise. Not sure if I believe them, but hey, what the heck.
When running the head unit cable make sure you leave enough slack to remove the head unit easily. Otherwise you'll be trying to unclip the Sirius connector from the head unit in a tight space. Zip-tie the cables on the bar behind the glove box, but don't tighten anything until you're sure you have the slack. They give you enough cable to do everything, but it's still heavy and not easily moved if you don't do it right.
