I am in the same situation. According to the Murano forum and my dealer, the receiver is the same plugin's but the antenna is not. I have my old Murano Sirius receiver and I am about to track down the XM receiver and see about swapping them out. Its supposed to be mounted in the rear, to the left, on the side. I did not get a firm price, but a Sirius antenna is supposed to be around $125.

I'll let you all know how this turns out.