I have been putting some sound deadening material on my '97 Tracker,  and so far it has been helping. I put some on the firewall before a trip earlier this year and it made a noticeable difference. Now I have pulled the seats and carpet out and I'm putting it down on the floors. Next I'll do the inside of the doors. This stuff is usually used by people who are installing expensive sound equipment, but it just generally makes the interior quieter for highway use. Not all that important for offroad, and probably not much use for a convertible, but if you have the 4-door and do a lot of highway driving, it's worth considering. The stuff I got is a black, tar- or asphalt-like material with an aluminum foil backing. All you have to do is push it down firmly against the metal and it sticks. I got mine from this place:
http://www.b-quiet.com/brownbread.html

I don't notice anything in my 4-door, but the stereo.

If I'm running 85 MPH with the windows down, I just turn the stereo up, until that's all I hear.  Oh, did I say I like LOUD music?  

huh, what did you say

Hey, Bobzooki, do your ears ring after a long drive listening to the stereo?

I said,

"DO YOUR EARS RING AFTER A LONG DRIVE?"

my subs run 147DB and my ears have never rung =)...and i listin to it that loud more then not lol =)

What did everyone say, I can't hear with all the loud music!

I don't notice anything in my 4-door, but the stereo.

If I'm running 85 MPH with the windows down, I just turn the stereo up, until that's all I hear.  Oh, did I say I like LOUD music?  

YOU THE MAN!

I kinda like hearing the natural noises of my Sidekick...  When I don't have the stereo blasting, I listen for anything that might be going wrong.

I can't wait to get my new muffler from Calmini and hear how it sounds once it's hooked up.

Maybe it takes older ears to appreciate a reduction in road noise. That's what the sound deadening takes away. You can still hear odd things like the rod coming through the side of the block or your favorite CD. Or maybe you guys don't do the same kind of long drives I do.  After 12 or  14 hours in the car, I can tell the difference in how I feel if the car is quiet. But, hey, to each his own.

Euhm,   if I don't hear my stereo I hear my tyres .... So it's pretty hard to listen for any noises that aren't familiar....