Hey Kevin, sorry to hear about the noise from the Cherry bombs. If the sound is coming from the floor boards in the passenger cabin you might have to use the Fatman in there as well. The other thing you can try if that doesn't work is use a product called LizardSkin,
http://www.lizardskin.com/ as it is used on street and hot rods to keep them quiet. It is sprayed on the underbody with the exhaust taken off of course and when dry is pretty thick. I used over 125 sq feet of Dynamat Extreme when I did my Mustang and it went from the firewall to the trunk. Hope that helps.