I have had an increasingly loud exhaust problem and knew it was probably the resonator. They confirmed this and replaced only that part. I had always heard good things about them, and now I know this for sure. There was no up-selling or circular logic.They did the job fast and inexpensive. I was waiting for the high price due to my car being German, but it did not happen. Because the back pressure has been restored, it feels more responsive on the throttle. And it has a cool bass sound now. Can't recommend the more highly!