Dealer activated XM audio but not NavTraffic or NavWeather and during the "how to drive your Terrain" the salesman said we would have to pay for them if we wanted the service. Looking through the XM literature that came with our Terrain it says we should get a 90-day NavTraffic trial just like XM audio. So I called XM to find out. Customer Service agent (btw, avoid the menu drill by dialing 0 at the first and second menu prompts) was very courteous and within a couple of minutes had a 90-day trial of both added to our account. I did have to activate a reset to get it working but that is all it took. Cost after the 90-day trial is $3.99 for either / $6.98 for both. You do have to have the NAV option for this service.