I just had a local shop (very good, very good reputation) put a D3 in my wife's 04 CTS. It works very well and looks great in the dash. They could not keep the DIC with the install. Looking at the OE unit that came out, I understand why. I don't know the degree of difficulty doing it yourself, but if you have a good shop do it, you will be happy with the results in a CTS.