Well, i tore out all my 04 cummins firewall insulation as it was pretty trashed. I heard stories of how it really didn't make a difference in cab noise. Well, that's incorrect. Just as mt tires are also noisy as hell which people said didn't make a difference in canmb noise as well. I think half the people on these forums are deaf. 😂. So, anyone have any luck with frost king or any other cheaper products to cut down on can engine noise? I know the frost king helped slightly on my doors.