Honestly saying, why do you think autofoam will help with nvh?

Harder material will bounce sound more effectively. If this autofoam will harden like concrete, wouldn't it amplify the effect of noise created?

I have been driving vios, wira, sunny, etc before I actually got Sonata(company provided) and Rio. The nvh is so much better on these, and what they did is add those soft mushy foam in the front fender (both Rio and Sonata) and also some sort of soft but thick material on the wheel arch rubber cover (for sonata only). Even for audio gear testing in sound proof room, they are using soft mushy foam to do the job, not using something hard and solid.