Well, from a previous thread I posted about my Zumo 550 on the fritz, a re-furb unit is on it's way, any day now. Well, now a friend wants to order a pair of the Sena Bluetooth units and I'll like to split the cost so I can wire one to my helmet. My question: Will the XM setup on my 550 play via Bluetooth thru the Sena? If it will, is it stereo? I know it will work on the new 665, but I'd heard grumblings that it won't work with the 550 because of it's lack of AD2P technology, or something like that.