Today i am looking at a 525i MSport 06 local version, magnesium engine, push start, all ok, only issue is the TV screen is 6" and no navigationCan someone advise me if I were to change to bigger 8.8" screen will cost me how much?Also, to add in Navigation module will cost me how much?I am considering a local version 525 and Japan version which need to change CCCAdvise appreciated