Review on 🚀 K&N Cold Air Intake Kit: Powerful Performance Boost | Proven Horsepower Increase | 50-State Legal | Fits 2005-2010 Dodge/Mitsubishi (Dakota, Raider) 4.7L V8, 57-1546 by Amicz Kakaruk

It sounds like you're sucking out the excess air. Before FIPK I only heard the engine speed. This really opens up the airflow and allows a lot of combustion chamber echo back into the air intake, which in turn creates a VERY whistling sound when the engine is under load. You won't notice the "growl" in the parking lot. When I finished and took it out for a test run, the first time I crushed it, the sound almost scared me. It looks like he has duals now. My 0-60 was cut 1 full second to 9.6 seconds by adding that and Airaid Poweraid. I also worked on my factory throttle body and am now 2-3 mpg better (25-27 mpg) when cruising at 70 mph on the interstate. Best of all, it's quite noticeable when stepping out of line, and it's quicker to pass others too.