Best way to connect a Iphone4 (for music not phone) to a concert Head Unit ?

Why not upgrade to a rns-e mate & use sd cards?

Could add an aux in 3.5 jack socket & use iphone to control tracks.

There are other devices, maybe a Dension unit.
 
I am also interested in this answer... Research till now has led me to believe, parrot mki9200 would be the best option (and also you get bluetooth, aux, usb)... And you get maximal control with the included display.
As I am aware the Dension units don't display anything on your headunit (Concert 2). And you are limited to only 6 playlists... And much more drawbacks...
 
I use the audi ipod connector with concert hu. Will play music fine. If you want it to charge iphone4 aswel you need a little belkin charge pin convertor adaptor. Have used it with all iphones
 
I really wanted ipod connection when i got the A3 but havn't looked back since installing the RNS-e! SD function is great especially with steering wheel controls
 
Isnt gonna happen mate, unless you use an overlay that is programmed as such with can signals for areas of the screen & modes.

RNS-E will be its last incarnation, as I suspect all audi's going forth will be fully integrated, not a head unit as such, look at the A1 & thats the lowest model, so the new A3 will be same or better.