I just completed the DVD Nav phase II installation. With Odysseus' help with cable and most terminals and his detailed instructions on www.cadillacfaq.com . I had to find and supply five of the C1 nav terminals which are difficult to obtain. His suggestion was to contact the local Cadillac dealer and obtain from the service departments' terminal repair kit. I dealt with the service manager. Once we got past the "you can't do it", it won't work, negative sh*t, my persistence, and his effort, he located the terminals. I paid $1 each. $5 total for the missing terminals. Odysseus FAQ instructions are EXCELLENT. Detailed and step by step. It took about two hours to complete. No surprises. Now, the DVD Nav/GPS retrofit is true factory with voice guidance and voice recognition commands. The voice guidance is a nice feature. The voice commands are GREAT! If you have a retrofit Nav system in your CTS with BOSE system, the Nav Phase II is nice addition and worth the effort. Thanks again to Odysseus for his effort on this project and his many contributions to this great forum. Also, thanks to Reed and www.cadillacfaq.com .