Hope I did not make you crazy with the book I posted yesterday. I found some very interesting information from my tech specialist at my dealer today. He has installed NAV radios in vehicles w/o Bose (UQA) systems. They do not get their radios from GM. The GM website shows their accessories for the NAV need the UQA option (Bose). NOT true...my tech gets their NAV systems from a company called Specmo. Thes are units that install directly into your vehicle. Specmo can take your VIN, and put in to find the correct NAV for your vehicle. I do know that you need an antenna, $49.00, the NAV DVD $300.00, a harness $49.00 and the Radio $1150.00. They number of this from Specmo was 20807045. By the VIN they can tell if your current set up will work with the NAV. I already had the UE1 (antenna) and I had the DRR Upgraded radio (UQ3). So, if your vehicle has at least these options, you can get the NAV, don't know about other option RPO's, you will need to specify to your dealer parts dept. to call Specmo with your VIN and they will give you the answer on your vehicle. Unfortunately, they sell to dealers only. But $1700.00 from them, compared to $2700.00 from GM is worth it. PLUS..I have no Bose system, and they guarntee this will work. In fact, my tech did an install and it came out fine, without a Bose vehicle, plugged right in the original harness and worked perfectly with the VCIM module. It is up to your dealer on whether or not they will work with you on this, I have a very long relationship with mine. My tech also said that no matter what you do, if you get a lock on a used radio, nothing can be done. But I uinderstand that there is some third party stuff available (LockPick?) that may solve these issues, but for the wiring, again, it is set to whatever RPO's were used in the original vehicle. Of course there will be dealer programming costs..It is possible to install yourself and save that cost for the programming. I really don't even know if programming is necessary...it may set it's self up through a user menu when it is installed. Just remember the lock code is the last six of your VIN.