I have done some foolish things with the platform

I bought a 223 Ls with no motor or drive, the Silent Tunder is attached, this being my first formula, I am wondering how this system actually functions, are thier pipes in there or does it simply fill with water and exhaust pressurizes under baffels etc. It seems wierd that all that hot exhaust, would pass around the inside of that fiberglass box. Than again I know nothing about Formula's except they dont look as good without the Platform, but thats my poinoin...