Something the salesmen (or sales women) do not normally talk about is that you can pay a lump sum and get a lifetime of XM (not including the Nav feature). This pays off only if you hold onto the car long enough. You can figure your breakeven point by calling XM and getting the best monthly deal you can and then ask them what it costs to get a lifetime subscription. Then just see how many years/months it would take to offset the lumpsum. If you have the funds and know you will hold the car that long, something to consider.