Date registered: Jan 2006
Vehicle: 73 280SE 4.5, 71 300SEL, 03 BMW Z4, 72 Fiat 850, 80 Triumph TR7, 85 Porsche 911
Location: DC Area
Mentioned: 1 Post(s)
Quoted: 95 Post(s)
I went to JC Whitney catalog (I think there's a .com version too) and bought some stuff that was a sandwich of foam, then hard rubber, then a bunch more foam, and topped with mylar. Or aluminum. My interior carpet was shot, so I took everything out and started putting the foam stuff in without heed to Mercedes underlayment or anything else (I also had the front and rear seats and center tray out of the car). I went to a local hardware store and got a gallon of contact cement. After cutting the foam pieces to fit, I coated the underside with rubber cement and allowed it to set, and did the same thing to the floor and tranny tunnel. I chose to have the mylar/aluminum side up, but I'm not sure it makes a huge amount of difference. On top of that, I glued a carpet set I bought online.
For two rolls of the stuff, I paid something like $80, including shipping.
If your headliner is off, you might consider doing the roof too, but with thinner (lighter) stuff.
I managed to do the entire interior, minus the area under and behind the rear seats. I went as high up on the firewall as I could.
I also sprayed some sound deadening foam into the interior of the door skins, but I'm not sure it made much of a difference there.