I used the LIzard Skin stuff on my Firebird and can say it so far hasn't made much of a difference in my sound levels. I have to wait till summer hits to find out about the heat, but I may not wait that long. I have Borla exhaust and even though at first they seemed a little more "muffled", it wasn't enough to make a big difference when my RPMs went above 2k. Under that I can control the noise and the little sound proofing it does helps, but as soon as I hit 2.5k the unlucky person in the back seat starts complaining. I have to really be conscious of when I shift when I have my 3 year old in the back. I have heard some good things about Fat Mat and they seem to be cheaper than DynoMat, I may be purchasing that for the Firebird.
BTW, my chally has a 318 with Flowmasters and doesn't sound anywhere near as loud as the 'bird. Don't get me wrong it still has umph, just not as obnoxious as the Firebird. I put down some factory replacement sound deadner and then lined the care with Reflectix for the heat.
Oh, and if you do decide to use Lizard Skin don't bother with their 150 dollar sprayer. Just use a 18 dollar sandblaster gun from Harbor Freight. What a rip off, it did the exact same job. The real key is steady flow from your air compressor and proper mixture of the product prior to spraying.
