Is there an xm module available to swap out with the stock sirius? I know gm offers a gm-siri module that swaps sirius for xm in all of their sat ready decks. I've had both so don't even start with the sirius is awesome argument. I'm in the OnA camp, and have been for years, music wise it really is a toss up if you listen for enough hours a day. Anyhow, just wondering if such an animal exists. (2008 gt premium convert, replacing '99 cobra convert.... happy valentines day for the wife.)