...the factory fitted one? do you the price for it?

Yes it would be possible for some serious money, the newer BMW's are very complicated the idrive would be very expensive, My advice enjoy your 5 series, just get one of those portable GPS garmin things, i know their cheap but when do you actually use a GPS are you a Business man always traveling, i had a navigation off a 2001 740i sport retrofitted into my 98 740IL but that is because i do alot of traveling about 70% of the yr.

if you are talking about the built into the dash one sorry bro, the system is built in by the factory and it has alot of components in it (like the idrive system and the little circle thing) even if you could install it aftermarket from someone who would be willing to go through the time and hassle to do so it might not work out the way you would want. This would also be really expensive (look into about 5-10G). If you want a aftermarket one fitted you probably can get your dealer to do it but it would cost a pretty penny (the dealers are always a rip off) it might also void the warranty. Consider going to someone in your city that will build you a custom dash. this way if you were to sell it all you would have to do is pop on the old one and you would be set. In my opinion wait a while before you do it. the warranty will end soon then the car is yours to screw with