Hi Cadillacats2013,
Can you share more details as I want to do the same thing to my 2013 ATS? Where did you get the HMI, who did the programming, what specific GPS antenna did you get, etc.
Thanks...

Hi Folks,
New to the Forum so making the requisite introduction. My ride is a used 2013 ATS 2.0T Sport, black on black, acquired yesterday, and I love it! Now I'm going to go trolling around to...