Just a piece of info from my experience. If you had a 396 with weather and wish to change it over to the new 496 you must have the 8 digit codes (Radio Id's) off the bottom of the XM antenna. Even though the old antenna fits fine it will not work...only the new one (I tried!). Then it costs $15 to transfer it. I am giving my 396 to my wife for her TriPacer...she shouldn't be flying in bad weather anyway!