The AirRAID 400-940 M.I.T. (Modular Intake Tube) is a direct fit replacement for the restrictive stock intake tube and silencer assembly with a smooth flowing, clean fitting intake tube that feeds air directly into the OEM filter box. All sensors and other critical intake components stay in their stock locations. Rumors of early models of this tube causing early 5.4 3V engines to run lean have been reported, but honestly that makes no sense. The computer should autoatically adjust for any / all extra air coming in past the sensors. I have noted no problems whatsoever with mine.
I am a little old school on this and run a K&N filter, yeah I know the oil from the K&N can, and indeed has fouled the MAF, it is easy to clean and everything beyond it is fine...
Since installing the tube, I have only had city miles on my truck, but in that time, I have noticed approximately a 2 mpg mileage gain from 10 to 12 mpg city. I know that sounds awful, but considering I am driving a lifted 4x4 truck with 35" rubber a winch etc... that is actually quite good. As long as I keep my foot out of it, I expect highway mileage to improve similiarly.
There was a notable, but not obnoxious change in engine sound with this tube. The truck now actually SOUNDS like a V8. In particular under hard acceleration, it sounds like a 4 barrel carburetor equipped V8, a much nicer tone than the overly quiet whoosh it used to have. Not obnixiously loud though.
Throttle response seems to be a bit improved, but again, this is a big truck, not a dragster...
And lastly, the looks, it just LOOKS better than stock, by a LONG shot... I never liked that oversized behemoth of an intake arrangement that was used from the factory.
I took the following photos the night I installed it. Sorry, I don't have any of the engine bay cleaned up and can't get any for a few days. My truck is in the body shop right now... You may want to boomkark this page though, I will try to post updated photos once I get my truck back from the body shop.
The Air RAID 400-940 installed on my 2004 5.4L 3V
The kit comes complete with a C.A.R.B. exemption
sticker for those unfortunates that have to put up
Overall I feel this was a good purchase, however I would HIGHLY recommend you pair it up with a quality high flow air filter, AND a tuner...