I brought my 2014 CTS-V which I had purchased from them in for service. I had it towed down because of a horrible squealing and shaking coming from the rear of the car. I got down there to pick up a loaner car while they looked at my car and noticed my car being pulled into the service area. After standing around awkwardly in the service area trying to figure out where I needed to go I finally asked the guy that drove my car in and he told me I needed to talk to Chris in a rude manner and walked away. Now I'm standing around awkwardly in the service area trying to figure out who Chris is. A guy named Al walked out of the service bay and I asked him where to go and he said follow me and walked in the office area and immediately got on the phone. So now I'm standing awkwardly in the office not knowing what to do. Finally the infamous Chris shows up and I tell him my name and my car and he immediately tells me it's my aftermarket exhaust causing the problem. I had to argue with him that it wasn't the exhaust and show him the video I took of the sounds it was making and he still stuck with the exhaust being the problem then he sent me to another service manager, I have no idea who he is because he never introduced himself. Here's the main issue I have, when I called and set up the service I told them that the shaking and squealing didn't start until 60-70mph. I get in the car to take the new guy for a ride and let him hear the sounds and I notice the odometer is only 1 mile more than when I had it towed. Somehow this service dept. was able to diagnosis my problem that only happens at 60-70 mph with out even driving it. The new guy and I take the car down the road and sure enough 60 mph squealing and shaking starts and his first words are, "yea that's the exhaust". I would like someone to explain to me how an exhaust makes the same squealing sound a rock in your brake caliper sounds because that's the exact sound it makes. When we got back they pretty much just wrote me off and never offered to fix anything. He said they could readjust the exhaust and see if they fixed it but it wasn't under warranty, ok well if that is the problem you are so positive it is then fix it and give me an estimate of how much it's going to cost. None of that happened, I was never offered a solution other than take it home put the stock exhaust back on it and then bring it back so they can look at it. They are supposed to be mechanics which means they are supposed to fix the issue not assume what it is and tell the customer to get lost. I don't know if it's because I'm a female and they thought they could tell me some nonsense and I would believe it or what but my husband who is a mechanic was standing there telling them it's not the exhaust and this guy that probably never had grease on his hands a day in his life was telling him he was wrong. This was the worst customer service I have ever had, I left in tears because I was so upset. I bought a $50k car from these people and they treated me like I was a liar and a fraud. I even waited two days for roadside service to tow my car to their place because I had such a good experience with the sales team. I wanted to be loyal, I could have taken it to the closest Cadillac place in town to have them work on it and in hindsight I really wish I had. I will never go back to this place and they will never see a dime of my money again. If you are female and go to the service dept. be weary and don't let them treat you like less than a person because they think they can spit out some information and have you believe it. The entire time I was there no one ever greeted me or asked me if they could help and that's basic customer service, if you hate your job as much as it seems maybe customer service isn't your forte. P.S. I went home moved the exhaust around and put rubber hose on all the metal that could possibly touch metal and drove it to work this morning hearing the same noise.