The one mostly referred to as the resonator is the centre piece. On my 420SEL there are just three pieces. The cat, centre resonator and rear muffler. These pieces all run close to $1000 Canadian. I got a few quotes from some US sources but after currency conversion and customs charges it would have been more expensive. I would suggest getting it from the dealer, even if it costs you $100 bucks or more than at a discount place. I checked my service records and on my car the original factory exhaust lasted 120,000 miles and 10 years. The second owner replaced it with ANSA, a high quality but cheaper part (probably saved $200, but they only lasted 50,000 miles and 4 years. I think the MB parts are worth it, unless of course you plan to sell in two or three years. Then it will be someone elses problem.