The expansion module is a part number PT296-12170, basically plug and play unit that piggybacks on the radio and adds nav to existing HU. As for aftermarket go to Crutchfield web site and pick and chose any double din NAV radio. For the $700 plus you can pick a unit that will have NAV as well as CarPlay and even iDatalink. IData can be integrated to car functions like displaying tire pressure, engine functions etc. So for the money you can have much more functions than just NAV. Many gust already have don the swaps and there is plenty of threads on the forum with pictures as well as many details. Good luck.