Dartmouth

This 997 I am looking at does not have XM. It also does not have universal aux input option. I must have XM in my car. Can it be added to the standard radio unit? Navigation is included with the car (in case it matters).

I've read it can't be added to the radio if it hasn't been installed when the car was built. If not what about FM modulater that tunes the FM into a specific station and install a small tuner unit in the car? I prefer to have it run through the unit in the car.

Any help on this?