I have not done it yet on the 350, but I did on my Corvette C5 and Cayman. The results in both cases were - let's just say the wife was very happy. I installed the Dynamat under the carpet on both cars when I installed the aftermarket sound systems. The Dynamat really killed the road noise - especially from those huge Vette tires. Not sure if the results will be the same with the SLK because it is a much quieter than the Vette or Porsche. I later put Dynamat in the doors of the Cayman - more for improving the quality of the audio (which it did). However, it did very little for killing outside sound.just thinking maybe I will pull the panels off the door and put the Dynamat in the doors as well as (I I get REALLY ambitious under the carpet in the car?
Anyone have any thoughts if i'ts worth the what...4-6 hours? THanks