There are two choices for adapters for your XM Direct unit. I chose the adapter that allows adding a CD changer as well--just in case I NEED one. The whole install takes less than 15-20 minutes once you find the connector behind the left rear wheel well access panel. I mounted the antenna just behind the left roof rack railing right on the roof and tucked the cable down the edge of the door seal.
It took longer to have XM activate the unit than it did to do the install.