K&N 57-1514-1 Performance Air Intake System for Jeep Wrangler 4.0 L6 TJ 1997 - 2006 Estimated horsepower gain of 12.13 HP at 4623 RPM Designed to improve throttle response and engine sound Lasts up to 100,000 miles before service is required (depending on driving conditions) Replaces entire factory air intake system Easy to install, usually in 90 minutes or less