Actually, I just checked both XM and Sirius's web sites:

GM - XM
DC - Sirius
Ford - Sirius
Nissan - Sirius
BMW - Sirius
Audi - Sirius (I assume this means VW, too)

Neither mention Porsche (though I do know I read that somewhere - maybe in a press release).

I'm not sure where on XM's site it mentions the pathfinder.
_________________________
"Nature has constituted utility to man the standard and test of virtue. Men living in different countries, under different circumstances, different habits and regimens, may have different utilities; the same act, therefore, may be useful and consequently virtuous in one country which is injurious and vicious in another differently circumstanced" - Thomas Jefferson, moral relativist