Supersprint Exhaust
Their systems are second to none and they use state-of-the-art technology. They probably have done more R&D than any other exhaust manufacturer out there. However, their systems are not cheap. A full system for the E55/SL55 will set you back ~$10K.
However, what most people don't know, is that you don't need a full exhaust system for an AMG car. AMG has a contract with Sebring (www.sebring.com) to manufacture their oem exhaust systems. Sebring is also known to be a top manufacturer and is right up there with Super Sprint. Sebring also sells a number of aftermarket systems in Europe and supplies exhaust systems for race cars as well.
That being said, you are not going to gain much from replacing the stock AMG/Sebring exhaust. However, you will gain alot by replacing the restrictive stock exhaust manifold with a good set of headers. For example, look at the package AMG offers in Europe for C55. They don't touch the stock exhaust system with the exception of headers. Some people also recommend replacing the cats, but I believe that the stock ones are sufficient.
From what I understand, Super Sprint is currently in the works of developing a system for the C55. It will probably be available in the next couple of months. If the price is right (i.e. between $2000-$2500), I will definitely buy a set for my C55. Principally, I have trouble spending more than that on a set of headers.
When and if the headers do become available, we should think about organizing a group buy.



