I am an audiophile. I like for my music to sound good in the car. I have looked into using different materials to deaden sound on the inside of my Z because I like a quiet car. We all know Z cars are NOISY! I tried an off-brand of sound deadening adhesive mat that is sold through MCM electronics. I suppose it deadened some noise but the application was a PITA and the adhesive started turning loose after one Alabama summer. I refuse to pay the going rate for Dynamat or other name brand materials.

My solution was to strip the interior, clean up the floorboards and hatch area and have a rubberized truck bed lining - Bullhide - sprayed in.

Bullhide was the only liner I have found that doesn't have a "sandpaper" type feel. It is smooth and tough as nails. You cannot tear it and it won't shred under weight. The local shop owner was very helpful and we discussed how I wanted it done. I made sure that the drain plugs were left open and that no wiring would be inaccessible. After all, this lining material is relatively permanent. Yes, the stuff is heavy and all you speed freaks probably don't care about noise so this is not the choice for you. I like the speed of my Z but it is still plenty fast enough and now I can hear myself think. The application cost me $400 (Dynamat would easily cost this much) and he laid the stuff down up to 1/4" thick in some areas.

I have seen one DIY liner that looks like a good option - EZ Liner. It sprays on and the kit for one bed is $129. I would guess that more would have to be purchased to lay it down thick, though. I got a sample of this and it is just like the Bullhide. They will mail samples upon request.

FINISHING TOUCHES
I did have to trim the drain plug areas with a razor blade and it took some serious elbow grease. Once that was done I used POR15 Por-patch to reseal the metal that was exposed so that no moisture would be able to get under the lining. Now the original body plugs fit nice and tight. The next step will be to waterproof the underside of the floorboards. I will use POR15 rust paint and may follow with a sprayed on coat of the DIY EZ Liner. That will come later, though, as there is still a lot of cleaning to do underneath.
Don't forget to leave the fuel gauge sending unit access plate uncovered. I forgot that and will have to cut through if the sending unit ever goes out.