That's the same tom foolery as these cold air kits they sell today. All they do is increase the intake noise, so it sounds faster. Those kits all claim 5-10 hp increase. I've got news for Ya, you gain 5-10 hp when the sun goes down. Good Luck.
Wrong. They provide cooler, denser air to the engine vs the hot air in the engine bay. Naturally a cold air intake provides a more noticeable change in gas cars - throttle response, slightly better mileage. Will not give as much benefit on a diesel, but if it helps ONLY with noise, then it's a win already.
I have aftermarket intakes in all my gas cars - Camaro, Equinox, Corvette - even in my Chevy 3500 RV. All i can tell you is i can feel a difference when driving them stock vs current.
This is what i just got done to my 1009. I knocked out the port cover on the grill, ordered the cover adapter from LMC and then got a 4" air duct hose by Spectre (Part N 9751) which came with the rubber adapter. Bought two 4" clamps and done. Maybe $60-75 in parts and hour of time.
Will need to rotate the front battery. I'm going to make myself a temp bracket using some metal straps and the existing hardware mounting bolts, but may have someone weld me up something sexier if i keep it like this.
Have not driven yet (getting seats re-worked), but will give you an honest reply on if it makes any difference at all.