I have the factory stereo in my 2011 tacoma. Toyota PN from the back is 86120-04171-A. The unit has Am/Sat button, am works but I get nothing for sat, so I assume the sat radio is not installed. Can I just buy a sat radio/antenna and a cable that fits my unit? I've done this on older vehicles but the guy at cartoys says I have to buy a hub unit too, all totals $600. Really?