i doubt there will be noticeable performance gains when it comes to an air intake system. the sucking of air from the intake system will definately be noticed. the air increase which enters into the system will be picked up by the 02 sensors and the fuel will be adjusted accordingly to maintain an "optimal" mixture. i'm not sure how toyota software engineers define optimal in their system. its pretty hard to fool the computer system. why dont you just install a booster chip or adjust the computer with one of them reprogrammers and im sure the performance gains will be more evident.
someone feel free to correct me if i am wrong, but in my old truck, i installed an open element and initally the performace gains were great. but once the system reset and adjusted to the intake mods, the car was the same. it sounded sweet in the morning when there was a huge sucking sound coming from the intake, but i bought gas just as frequent as i did before the mod.
