Sound Deadening products

Has anyone used products like Dynamat or FatMat, etc. on their car?
I'm sure everyone would agree with me that the D15B7 engine noise is annoying inside the car. I was thinking to use something like Dynamat to kind of make it quieter inside the car. Any thoughts?
Also, if I was to do this, where would this stuff be placed? I know that for audio people put it in the usual places such as doors and the trunk.
Comments are always appreciated!
-John
I'm sure everyone would agree with me that the D15B7 engine noise is annoying inside the car. I was thinking to use something like Dynamat to kind of make it quieter inside the car. Any thoughts?
Also, if I was to do this, where would this stuff be placed? I know that for audio people put it in the usual places such as doors and the trunk.
Comments are always appreciated!
-John