The inside of my 89 is extremely quiet (except for my pesky little exhaust leak). I have dynamat extreme throughout the entire interior...doors, back panel, and floor. If I stay easy on the gas (to keep from having the exhaust leak) I can hear my radio extremely clear...even when it is at a low volume (actually sounds like I am not in an old truck and in something a lot newer). I have 35 toyo open country's and a single cab. Definitly expensive, but if you want a quiet truck and not have to crank your radio on the highway I would get it (easy to install). I know on my next toy I will buy it to cover everything (since it would be a DD too).
Also, I have a Rockford fosgate stereo (9 speakers and 2 amps) and it seems like what they say on their website is true, all my music is really crisp and clear (and my doors close nice and quiet).
