I remember years ago one or two members changed their head units. It does require custom wiring work of course, and you have to remember that the stock head unit also has the navigation voice in it, so you will lose your nav if you change. Probably not a big deal these days since whatever you replace it with will probably either come with google maps or have easy phone integration for running maps on your phone. Back when these 06's came out the
iPhone wasnt even invented yet, bluetooth music was just about to become a real thing, the
Razr phone was the big deal, and there was no good google maps on phones since there were no smartphones yet. lol. So most people back then didnt have easy maps integration on new head units.
My main gripe about these old cars is lack of bluetooth music streaming, as phones are moving away from headphone jacks. So a while ago I bought a bluetooth receiver from amazon with A2DP, AptX, and Bluetooth 4.0 low energy and all that. I plug it into my rear cigarette lighter and leave it under the seat. So now my car has bluetooth audio streaming. Doesnt integrate with stearing wheel controls which sucks, but if your phone support music control with the volume buttons while the screen is off then it works pretty well.