In-built Satnav. Little or large screen?

[minerva]

Does anyone on here know the difference between the little screens that BMW used to use (up 'til 2001) and the bigger ones it used before idrive came along. I don't see why it should be any different, but there may be some sort of major software upgrade in the SatNav?

[minerva]

So... the nav improved from 2003 and not with the bigger screen? Is there any way of telling which system a potential second hand purchase may have?

Thank you for the info, btw