It is really hard to find information on forward compatibility of stock components especially with the SYNC system. The software can always be updated to keep Navigation, etc. Up to date.
However, after a lot of research, I can answer your question at least through the model year 2007.
I have provided you with a diagram that has the part number for your head unit, (Audio Unit), which is part# 6L3T-18C869-AC. You will only see the 18C869 of the part#.
The only possible complication I found was whether or not you have the AUX port for IPOD, etc. And the Sirius hookup or the Audiophile unit. I could not find out if the Sirius is installed in the Head Unit that you have which seems to be the same part number for 2004-2007+. So, it seems like it should be there, you may already have it. As far as the AUX port, that is impossible to tell from any of the diagrams that I found. However, Ford makes an adapter if you don't have the AUX port. Here is the link for the Ford F150 Store where you can get the adapter;
I also have the stock dash diagram which has the part number, I think I already mentioned this, or part of the part number that is important for identification. It shows locations of the connectors as well.
It seems like messing with the SYNC system, depending on what type and how intricate it is, can cause a lot of problems. It is something that is mostly deemed not compatible with aftermarket radios. So, if you want to upgrade, you are doing the right thing as going any other way is going to cause problems.
I hope this information helps.
Sunday, October 30th, 2011 AT 2:02 AM