not sure on the warranty mine is a 16 so it’s already out of the cadillac warranty. Main thing I like is the sound. Def feels a little low end for sure, but it sounds awesome. Not too loud but loud enough you can hear that 6.2. I’m gonna tune it and out an air intake on it and those 3 things together will make a huge difference in performance. As far as gas mileage I was getting 21.9 todaylooks and sounds so good. let us know how they change your mpg and performance.
I think I want them. does it void the warranty?