In my case, the tire change was only part of the battle, thouth. The other half was the Dynamat (Roadkill brand in this instance) installation. The improvement was a combination of both actions.

For anyone interested, it cost me $734 to have the sound isolation/insulation stuff done.

I also had dynamat placed in the hatch and doors..$1200.:(.guess they know a sucker when they see one!

Interestingly enough, when I checked by phone over two weeks ago (before buying the car) I was quoted "around $2 thousand" to do the whole car. But when I went in Friday it was a different story. It took one man all day, and he used 4 pkgs of the stuff so far. So the material was about $370, and the rest was mostly labor. I'll have to pay some more to get the cabin floor done, but it looks like about half of what I first expected for everything.

I was quoted about $300 each for hatch and doors so around $600 total if I wanted to do both which includes materials

That is really effen good. If the noise is that bad, I would probably say jump on the deal.

For the ones that have used Roadkill or Dynamat have you noticed a night & day difference?

Since I have HFCs, I don't notice the road noise as much, haha.

My experience with Dynamat was that there was that there was a slight difference when I did the hatch and more when i did the doors. (There is NO sound insulation in the doors) The two added up to a significant change, not night and day difference but significant.. and when I put on new tires there was even more..

The point being that, to me at least, no one thing made a "night and day" difference..but all three together did. It's still "sports car loud".. enough for me anyway ..but a lot more pleasurable especially on long drives. Guess if you're on the track it really doesn't matter..

Funny thing is that the other day I was driving my wife around thinking how much better it was..and on her own she mentioned that she thought it was loud!
She is used to an Accord sedan.

In my experience I went from really thinking I had made a very bad mistake to driving it every time I can with a big smile!! :) In fact I am about to go for a cruise right now! :)

What we really need is some accurate sound measuring device that can tell exactly how much difference these mods make..Anyone?

:iagree:

Yeah, I've got he same exhaust / HFC set up as you and it's like 'What road noise?' Unless you're coasting...

For me, I'd say it cut the sound levels in half or more. That still doesn't make it like a Mercedes, but now you can carry on a conversation on the highway without shouting. It's definitely worth the trouble and $ for me.

One thing I forgot to mention that might be of interest is that now I can actually hear the sound system, too - whereas before it was really contaminated by the road and tire noise. There was a major difference there, IMO.

Here is a good link to information on what to cover and how much to use from a guy that did a lot of product testing.

Sound Deadener Showdown - Your Source for Sound Deadening Products and Information

EDIT: this is not the original data he had posted years ago comapring all products on the market, seems to be selling his own stuff now. I think there is still some good info here though.

I can actually hear the engine better which to me would mean a better sports car experience..

I think your report is accurate Charlie. I dynamatted my doors and small areas of the hatch last week. Not a considerable difference, but it is noticeably quieter. I can hear my motor and speakers more. I may add more Dynamat along the rear speaker area if I decide to add rear speakers.

I have thought about this: there is a stretch of freeway that I travel that has various surfaces and really plays a symphony, or rather cacophony with the tires. The thing to do would be to use a recording measuring device and travel a certain section of road, long enough to get a good reading. Maybe 10 miles. Stay in one lane, at one speed as much as possible, A/C and stereo off & windows up. Take a measurement maybe every 10 seconds with the microphone in a fixed location, like attached to the inside driver side headrest strut. Install the Dynamat & repeat the test. Print out the graphs or plots and look at the difference in SPL at the same locations and elapsed time. There you go.