Not sure which 2004 Lexus IS 300 Air Intake Systems are right for you? We have over 89 customer reviews, with an average rating of 4.5, to help you find exactly what you're looking for. Megan C from Corona, CA said, "I was not sure what to expect with this product. Turned out is was very easy to install (came with detailed instructions) and has resulted in a noticable performance gain. Plus at about 3800-4000 RPM it sounds great."