Ipod hook up for factory nav

[glennf1]

I'm also researching these to purchase one soon. I don't have the factory XM tuner behind the glovebox so the model I would need connects behind the radio. My only complaint about these is that the factory radio does not change the button labels to the iPod buttons. You have to remember which buttons are now shuffle, forward, back, etc. even though they read out for XM tuning.
Check out eBay also, there are many models on there.