From a previous reply:

I went with the ComanderMT. It works great now that I found a great place for the antenna . I was originally going to install the Cayenne unit but at the time I was getting error messages from the nav system stating system failure. The dealer found that it was a defective CD player. In retrospect the Cayenne unit would be better for the simple reason the gear shifter gets in the way of changing channels. Also, the CommanderMT is quite bright at night, out illuminating all dashboard panel lights. All in all the XM unit works fine. It's a lot cheaper. I have attached a jpg to show the installation. The XM antenna is a micro antenna.

I found a great place to place an XM antenna. By placing the antenna in the middle of the metal rollbar plate it gets great reception with the top up or down. According to the installers, the antenna works best with metal beneath the antenna. See attached pic. 

 In retrospect, I'll probably have the Cayenne unit put in at a later date because the CommanderMT is too bright at night.


Best