I used D&A Old School Automotive for my SS. I did it I think 3 years ago. They were MUCH cheaper than Gardner. I can't say about concourse quality because I don't know concourse. But I can say my head pipes were original GM and the D&A head pipes were spot on. Every bend, bulge, and dent. The system was a breeze to install. I may have taken some picks of them laying side by side. I'll see if I can find them. Dale
http://daoldschoolautomotive.com/montecarlo.html