I run a 55 AMG exhaust on mine with the resonator removed. Sounds Great. I have personally dynoed a 430 with stock exhaust then removed the muffler to install the eismanne exhaust only to see a 7hp loss.LOL. After seeing all these other companies trying to sell there product I would have to say IMOP that genuine AMG takes the cake in style,looks,fitment,sound, and power gains. How much money do these other companies have to R&D their mufflers? As much as MBZ??