I got a 53 231 with sat nav and want to change head unit but do not want to lose other functions such as air con, sat nav, auto clim control anybody out there done it successfully?

If so what did you go for.

OK disregard first post looking through websites etc it is far too expensive to do this. But looking at getting an xcarlink into the back of the HU looks a good idea for my iphone with the blue tooth option sounds promising.
However with my factory fitted dvd sat nav. Does this go into same port as the xcarlink, meaning that I cannot have both or will it be OK?
many thanks for any information given.