What's The Difference In A Early 2000 E320 C-nav System And A Late 2000-2002? Diff?

[JAMIE2000MBC230K]

I'm Searching For Comand Cd #4 (south Usa) For An Early 2000 E320..they Say It Has A C-nav System...the Cd's On Ebay Will Not Work. The Dealer Says The Early 2000 Model E320 Has A Different Nav System Than The Later 2000-2002..it Looks Just Like The Comand 2.0 Navigation System On The Other E320/430's.....the Dealer Wants To Rip Me A New One On A Entire Set.....is Anyone Else Aware Of The Different Nav Systems For The Early And Late 2000 Model E320.....i Have The Navtech Cd's And They Won't Work On My Early 2000......can Anyone Help Me Out Here? I Need Some Good Information About This C-nav Comand System...........