Summer 2006 I took out the whole interior of my 2006 Yaris to apply sound isolation.
The Yaris is truly a thin car of steel and plastic. Needless to say it offered very poor sound isolation on the highway and in urban areas. This was bugging me seriously. Hence, I decided to isolate the whole car. The materials used were Raamat BXT and Ensolite, both sold by Rick at raamaudio.com
Here is what my car looked like in the middle of the process.
Pentax Optio MX