I just installed Injen's cold air induction system in my '04 TL and, man, what a sweet sound! I couldn't tell any difference at rpm's below 4k, especially under normal acceleration, but once you open it up, above 4k, the engine sound is sooooo beautiful! I had heard that the Injen system made noise, but I always thought people were referring to air, not engine noise. I would have paid that much just for the great sound! It's the best of both worlds; no change in every day driving, and a nice (but not too loud) growl up high under heavier throttle!

P.S. Any of you who have installed the Injen by taking the bumper off: Did you have any extra plastic clips when you were finished? I have four that I cannot for the life of me figure out where they go. I thought they may have come off of removed pieces, but I don't remember the old intake having any of those clips. I am going to have to find a diagram or start taking stuff back off when I get home. I'm guessing the lack of clips won't cause any catastrophic problems from a 20 mile drive.