Replacement exhaust
 

Does anyone know who makes good replacement exhaust systems/components that work well, fit properly, and last like an exhaust should? I saw some made by "Bosal" for a good price online but I don't know how well they fit as a direct replacement. My car is a 1999 A6 Quattro with the 2.8L engine. Someone recommended getting a used Audi exhaust system, but I have no idea what that would cost or how much more one will get out of a used system. I probably will have to replace one or two components at a time. I definitely need the center muffler/resonator and the passenger side catalytic converter/flex pipe.