External XM AntennaI know you will be concerned about drilling a hole through the roof, I was. Remove the privacy curtain holder in the overhead bunk. A long 1/4 drill bit, drill a hole from the inside through the roof. I centered it. The antenna wire runs down through the hole is under the privacy curtain holder down the side of the bunk over the passenger door and into the dash. The antenna has 3 screws to hold it to the roof and then Dicor lap sealant the heck out of it. Viola! Took me about 45 minutes. I get full bars XM reception everywhere. Been from NH to the Keys. If you're worried about doing it yourself have a dealer/pro do it. It's well worth it. You'll be extremely disappointed if you try to use the stupid magnet antenna. I sure was.
Good luck.