You have my vote for Mac peformance in terms of sound and performance. See my signature for my exhuast setup. No, I dont have any sound clips so don't anyone ask lol.
As for quality, I won't lie. The Mac HTS coated parts will loose their HTS coating over time and will likely develop rust. This can be prevented however. You can get them ceramic coated by an exhuast shop, which won't be cheap. Or, you can do what I do. Go to the local auto parts store or Wal-mart and purchase a can of aluminum colored exhuast paint. Its high heat resistant and contains some ceramic. It will help add another barrier of protection over the HTS coating. Apply a couple of coats before installation and let set over night. It works great. Also, regularly check the exhuast every few months to see if the coating is flaking away. If so, no problem. Just spray a bit more on. Its not too expensive either. About 4 or 5 bucks a can.