I did that couple months ago. I have H/C car with no cat, and it is loud as hell. That was my first mod and it was great...
I used 100sqfeet of the damping foil (similar to dynamatt but better and cheaper), and 15 cans of sound deadening spray (see pic)...
I took all interior pieces: Seats, carpet, door panels everything...Than cleaned the floor with some brake cleaner and install the damping foil.
Next day I sprayed the undercoating. I had to wait 2 more days till everything will be dry, and install back the interior pieces...
It was worth the hassle. I paid $150 for the damping foil and $50 for sound deadening undercoating spray.
Now the car is much quiet inside. It feels much tighter inside, and there are no more noises that going from underneath the car (road noise). The only thing Sound deadening didn’t fix is the exhaust tone. My exhaust was just too loud for it, so I welded in 2nd muffler (chambered style) and it fixed the problem..
Sebastian
ps. Here are the photos...http://community.webshots.com/user/1995camaroz28

 

I bet you added a lot of weight too.I just crank up the stereo more. If its too loud.you are too old...

 

you didnt by any chance know the weight of your car before you did that did you? ive always wanted to do this, but was afraid of the weight difference. did the 100 sq feet of damping foil feel heavy to you at all?

 

Total weight that was adds was not more than 50 pounds...Adding 10RWHP more is like taking 100 pounds off my car, so I will just get that.
Sebastian
Ps. I am not really concern about weight…

 

Where did you get the dampening stuff.. What kind

 

You can just put that right back into your *** where it came from.


Thanks!

 

I put down 50 lbs of fatmat and it looked exactly like that. I put a full 25lb roll in the hatch area and the other role covered the cabin as well as a sheet inside the doors.. I noticed some road noise was gone but I have come to the realization the only way to kill the exhaust sound is to quiet my car.

 

Looks like you didn't clean the surface befor you put the stuff on? Did you use a heat gun when putting in on? If not the stuff may not stick after a few months. You should have also put some into the trunk area where most of the exaust noise comes from. As long as you are happy with it though that's all that matters

 

elemental desings
Sebastian

 

I used about 30 square feet of eDead (Elemental Designs branded) in my car. I did the doors, the upper hatch, and the lower rear well area. It REALLY quieted my exhaust, and the speaker rattles which were previously heard on the outside of the car, are completely gone.

I'm satisfied.
I'm trying to think back as to what the UPS box said the shipping wieght was, and I'd bet it weighed in (with the box and backing on the eDead) at around 20 pounds.

Also:
Edead (and all? of ED products are cheaper with the codes found here)

 

hows that stuff work on creaks and overall rattles when going over bumps?

I'm guessing that stuff is unavoidable...

PS.. If you daily drive any loud car for a while, one day you will "grow old" and want to quiet things down.. unless you've gone deaf..