AO Silver Member
Join Date: Mar 2003
It does reduce noise but that's a consequence of its real purpose - power & torque.
In engine design, the main destroyer of efficiency is the stop/start of air flow caused by the valves opening and closing. During development you chase inlet tuning to reduce this effect. These days the best designs feature a long tube to give low speed torque together with a resonator to absorb the valve pulses.
There are now some pretty good inlet tracts that manage to maintain torque for low speeds while allowing excellent power delivery at higher speeds.
Manufacturers spend months and months in engine test cells perfecting these designs. Quite frankly, removing them, is madness. I would expect a drop in power across the range but a bigger hit on torque.
Also, remember noise is energy. If you have more of it your losing something.