i at the stage now of putting the carpet back in so not quite shore of what to go for the mass backing on the carpet is not in a that great shape i have just had it all welded now and i planing to change the carpet in the next 2/3 years down the line.

 

I'm not a fan of all that sound deaden stuff when you can get the same results from just having Mass Backing put on when you order your carpet.

 

I had the interior on my vert out a few years ago and noticed it had zero rust. I got some 3M rubberized undercoating and coated the entire floor of the car and also up into the sail panel and around the rear wheel openings and kick panel area. I used 4 or 5 cans to make sure the car would never rust. I have noticed that it has helped a lot with sound also. It is mainly rubber based and does not have that asphalt smell like some of the other similar products. The car will never rust and it makes a noticeable difference with sound. The carpet has the thick backing which also helps. I can't hear the fuel pump come on when I turn the ignition on now. Before I could hear it whine when I turned the key on. I used several coats of the 3M stuff especially in the lower areas where water could accumulate.