[HummerHawaii]

This is the reply i got @ Zoomers exhaust..

Hi Lito,

The H-3 System has a muffler. We just call it a vortex exhaust chamber. Its
legal in all states and improves emissions because it burns less fuel. Its a
bolt-on and fits in all factory hangers. However we still recommend to at
least tack weld the system in as well because clamps can come loose after
time. But not required. $899.00 free shipping. No dyno results at this time
but on the average you can expect 14hp and 15lbs-tq not to mention 2-3 more
miles per gallon. Give us a call to place your order. We will ship same day.

Thanks,

Frank Arlasky