Went there to get my 300s some bark. Started with the FM40s left the resonators on. It was more but wanted a little more. I have them remove the resonators and was the sound I was looking for. I kept the resonators incase it was too loud later to my ears. Glad I kept the sound was perfect but not at 2k rpm. That was loud in the car. Wish it was not that at that spot other then that it was perfect. May sadly put back idk give it some time. The place was friendly and was easy to work with and listens to what you are looking for. They seem to work in all cars and issues and would recommend them to anyone hands down. There are a few auto places in the same complex but avoid and go to them.