It's not exactly plug 'n play, haha! You can make it work though, IIRC, all you need is the GPS antenna. Don't me to that though.
It's CD based maps, do you have the discs?
I believe you need to tap the VSS signal in the '01. The conversion is in the stickies somewhere. It is an antiquated system though. Your cell phone GPS/NAV is a thousand times better. For the price of the used nav unit you can get a better new aftermarket unit.
1996 - 115k - Too Many Mods To Mention. Ask or search! 1998 - Pretty Much Stock Beater / Experimental / Parts SOLD 2003 Cadillac CTS - 80k - Some Mods