I also posted this in the Audio/Electronics Forum:

This goes out to anyone looking to buy a glass mount XM antenna. Do not buy this product!! I have had to buy three of these products because they would fall off the rear window. I contacted the manufacturer, and told him of my troubles. He said that he could replace my glass mount antenna. I told him I didn't want another one, as if the first 3 didn't work, why would a fourth. He said he would not switch it for a roof mount (roof mount is cheaper), just replace with the same product, and was rude about it. I have told him I will never deal with them again, buy their products again, and would spread the word of their lousy product and poor customer service. Do yourselves a favor and stay away from this product. FYI the roof mount seems to be working ok for those looking to get an XM.

 

My SR2 is working like buddah' *inside* the glass. You cut a small metal piece under it (Home Depot $3.50). Just about an inch over hang around it. Put some velco (hook side) under there so it wont slip, spray paint it to match your deck, run the cables to the Sub grill and into the truck.. then enjoy XM with a stealthy-er install.