I purchased an exhaust system from them. They neglected to advise on oxygen sensor extensions so a week delay waiting on those parts. The system did not fit correct and when I took it to my local garage they noticed on th elift that the brackets installed by PYPES were not in the correct location. They wrote a work order which I shared with Amercian Muscle to identify how they would help. All advised by thier representative. I then went to Midas who concurred with my local garage. I had supplied documentation and now decided to fix my exhaust by having the brackets cut off and positioned corrrectly and welded on by Midas at a cost of $283 plus in s few weeks the original install caused the $62 brackets to break. American Muscle took a week to tell me I shoudl have waited for them to get back with me. Since I provided work orders and pictures I felt they would want to help with an adjustment. They said that I am on my own since they did not pre-approve the work that needed to be done with the recomendation of two differnt shops. This is not the way I expect to be treated by a parts company and I woudl recomend to everyone reading to go to a differnt supplier for thier mustang or any car parts.