The original exhaust is straight through. The internal pipes are perforated with fiberglas sound deadening material surrounding. Works well, very little back pressure, but collects moisture. Baffle type mufflers and resonators are not correct for these cars.
Original systems are all weld-up, very difficult to install properly and they seldom are done correctly. A poorly installed exhaust can ruin the ride quality of the car. It takes me five to six hours to properly install an entire all weld up system these days. Mercedes changes suppliers from time to time. Recently I got a factory new system from Mercedes for an early 230SL. The front pipes were about 1 1/2" too long making the exhaust hang down too far in the front. I had cut out a 1 1/2" section of each pipe and re-weld them before the system would hang correctly. We noticed that these parts were now being manufactured for Mercedes by Gillette.
