Harmonic pulsation / Vibration?????????

"Exhaust System

DMA (digital model assembly) found room for added muffler volume, a major factor in reducing exhaust noise. Conventional rolled construction further reduces noise because the outer shell has less tendency to resonate than did the previous stamped construction. To prevent exhaust noise from being transferred to the passenger compartment, hangers that support the muffler attach to the rubber isolated rear suspension cross member, providing a second level of isolation compared to the previous body mounts in these location. Hangers have improved isolation characteristics.

Two resonators are used with all power trains. A computer program was used to design the muffler and resonators silencing systems and position them at their most effective locations. One resonator is located under the floor and the other just forward of the tailpipe outlet. The muffler
is placed transversely beneath the rear suspension cross member-a location proven to be highly effective for noise reduction. The exhaust system for each engine is also individually tuned for quietness while providing a pleasantly perceptible sound under medium to hard acceleration."
http://www.allpar.com/model/lh2/conc_noise.html