:bouncy: Yes, you can add the Nav system to any year CTS. The newest Nav you can find will be the best. Make sure you get a DVD Nav and not the CD based. eBay is going to be your best and easiest source. There are junk yards. Most members who have bought off of eBay have had good luck with their purchases. Most DVD based CTS Navs run around $1000. Some a little less, most more. A new 2006 DVD Nav just sold last week for around $1450. It was new, almost all on eBay are used. Nothing wrong with used as long as no physical damage and it works. The only problem you'll have with the non-Bose system is you won't be able to add the voice guidance and voice recognition commands. Without, these, the Nav is still a wise investment and is fully functional. If you're serious, do a search on eBay and find out what the CTS DVD Navs sold for. Determine what you're willing to pay. Check eBay several times everyday. You'll find one soon. Good luck!