Is it possible to fit the factory SAT NAV system to my BF GT after delivery of the new car?

The GT brochure states this can only be done at the time of the vechile being built, however the saleman said the new system the BF is using enables the factory SAT NAV to be easily installed after the cars been delivered. Whats the scoop?

Thanks.

From what I know all the features are there for this, there is the room for the DVD in the boot and I think you still need to replace the headunit with the colour screen and remote sensor but there are other places (other than Ford) that will do this for you and maybe even cheaper than ford is offering.
Don't know if this is much help at all but i must say they are a good thing to have, nice screen too...

GT's already have the colour screen and the remote reciever... except BA MK1 GT's anyway...