I have a Gardner deep tone exhaust (with concours show package) on my 68 convertible. It fits beautifully, looks perfect, and sounds very nice. As noted, not cheap. The guys at Gardner were excellent to work with.
PS:
My only issue is regarding the sealant they supply for the exhaust joints. The sealant that came with mine was an acid-cure clear silicone sealant. This means that it reacts with moisture in the air and produces an acid when it cures. IMO, not what you want in a $$$$$ exhaust system. I used non-corrosive Permatex Ultra Grey at the slip joints instead. They guys at Gardner say the original sealant was clear, but I'm OK with the grey as it isn't noticeable at all.