I've read a lot on here about the dreaded Flowmaster drone and took my chances and had the cat back system installed on my 300c last week along with a K & N intake. I love it. There is a little bit of a "drone" when the MDS kicks in but honestly, if I hadn't read about it so much on here, I probably never would have noticed it. It's definitely not anything that is so noticeable that I wouldn't recommend it to people. I always have the stereo on ( and not cranked) and can't hear it at all.