well first off i want to say that i have a 2010 Reg Cab 4x4 5 speed
and second i would like to say i am no dummy whenever it comes to intake systems on newer vehicles (i built intakes for the newer model civic si's)
This truck had some major suffering in the hills here in WV and i was constantly having to gear down to make it up them whenever i should have been able to at least stay in 4th. (that was my main complaint)
So i want to say first off i bought a K&N intake for a great deal from a member on this forum,
K&N first impressions, i think they did a good job with the design and fitment of this intake system, a complaint i had was that you can not fit the filter flush with the heatshield as the vibrations and noise will drive you crazy, so i can see where there would be some engine compartment air that would make its way into there.
Driving, the K&N took a little bit to adjust on my truck and still never ironed out the idle issues, and i think it solely has to do with the MAF placement VS where its placed on the stock box, its too far downstream, Also when at a stoplight for a long period of time the truck would idle and then drop down to where it almost died out and then would kick back up (keep in mind everything was installed correctly)
Upon hitting the gas i realized the truck did in fact rev much more free. And the sound inside the cab past 3k RPM's was very loud. Could i tell a performance gain... possibly more of a placebo effect of the noise being so loud. However one thing i did notice was that the Truck was now able to go up hills without downshifting, so i knew there was a difference made somewhere. i was also able to hit 159.2 miles before the truck dropped below 3/4 of a tank (this was driving very very slowly and easy) and pulled of 23.5 miles per gallon.
Now i have since switched back to the Stock airbox, Secondary filter Removed, AFE Pro Dry S drop in filter, and the Fender resonator Removed.
Now i can honestly say this made the biggest difference in the truck, The truck is alot more peppy even over the K&N intake what i did lose was the annoying loudness at higher RPM's
The truck is able to pull through the revs just as easy as when the K&N was on, Removing the fender resonator i feel helped out alot because i am able to pull hills just like before with the K&N intake installed, Truck just drives the way it should have from the beginning,
Sound is similar to stock with a little bit more grunt but nothing annoying at all, you do hear the air wooshing in at crusing speeds though, more neat sounding than annoying.
spend the 38.99 for the AFE drop in remove the secondary filter and the fender resonator and you will have a better performing intake than the K&N IMO, i have yet to run through a full tank on the Stock/AFE setup so to be fair i dont know if gas mileage will improve as with the K&N, But the benefits are this,
Stock box has the pelinum still in tact over the motor
Stock box has the Correct MAF readings in place for the ECU
Resonator, Secondary filter, and Stock filter are about the only restrictions to the stock intake and with this they are out of the picture.
Overall i am just confirming what everyone else has said save your money buy the AFE drop in and spend a little time removing the restrictions that your factory intake has.
Keep in mind the secondary air filter is for emissions (but we dont have that testing in WV) the Fender resonator is for nothing but sound deadning.