What kind of sound deadening does the tC come with? Is it just a foam mat, a spray, or a sheet adhesive like Dynamat?

 

Not sure if this answers your question:

http://www.freewebs.com/johnrussell99/lowvibra.pdf

 

excellent, thank you.

So it looks like the tC dampening consists of strategically placed foam dampeners. Some Dynamat Extreme should help greatly.

 

or brown bread...;) stuff is much cheaper and works just as well...

http://www.b-quiet.com/

just saying since my friend bought this and it worked well... and dynamat extreme is just so expensive

 

I've used hi-temp mastic adhesive-backed damping sheets before and they worked well. It looks just like dynamat but is less expensive.

http://www.mcmaster.com/

 

It's more than just that. It's undercoating, other sound absorbing panels and materials, as well as suspension mounts and motor mounts that keep road noise out of the cabin.

Help what? My tC is the quietest car I've ever driven.

 

TC has a ton of sound supression items.

Aside from the foam, any cloth makes a halfway decent barrier. There is also the styrofoam under the trunk floor that will supress some noise.

The worst problem I noticed in the car was tire howl. However, I test drove a car with 18s on it and the TRD exhaust. Even with all of that, it was quieter then my DSM which has a whole role of Brown Bread (like dynomat) inside it.

If your really serious, look for a foam solution that will absorb noise, not just reflect it.