We have the incredible Swift Racing Air Intake system available for the IS 300. This kit is a true performer and comes complete with an ECU modification and an entire intake and heat shielding system. The dyno does NOT lie and this kit produces over 12 rear-wheel-horsepower and over 14ft.lbs of torque improvement!!! You can feel the difference in the seat of the pants. It wakes up this derivative of the Supra 2JZGE motor with a nice sound and great performance!!! No one gets 12+rwhp on an air intake system, but Swift does it with fine tuning of the air/fuel maps and with a great intake set-up.
A great side note with this set-up is the real-world reports rolling in of legitimate 10% increases in fuel economy. If you drive like John Force does in the 1/4 mile then don't expect miracles.