Hi Folks. I have been searching the forums but can't find a reference to upgrading my nav system from MkIII to the MKIV. Forgive me if i've missed it!

Am I right in thinking its just a matter of changing from the CD unit to the DVD reader, or is it something more sinister?! Any advice would be great. I'm driving a 08 / 2003 X5

Many thanks in advance.

Matt