If that's that case, why seal the fire wall....let all the sound and oh by the way the fumes, heat and Carbon Monoxide from the engine compartment directly into the passenger compartment....that's real smart....
There's something missing in this line....details....
"They put a tube from the engine compartment to the passenger compartment to carry the engine sound without making the exhaust too loud."

All I know is that my Challenger doesn't need any type of tube to bring the sweet engine sound to the passenger compartment!!!!