Martin screw the 24.5lbs of added weight.
My ears are still ringing for when I drove my car from the docs of Southampton to my house with no sound insulation and a screaming straight through exhaust.
And I am not joking. I suffer now from tinnitus and when everything is quiet I can just hear the constant ringing.
Children's hearing system is even more delicate.
I will follow on your steps and add 25lbs of sound proofing myself....
Acutally after seeing how great of a job you have done I might just drop my car over there one weekend