2.7 air intake

ok so im reading some forums and saw some pictures of someone taking a "2nd filter" or something like that out of the intake system does anyone else have any information on it and how to do this because i would like to do this. and with it saying it will save $300 instead of buying a new intake?

does it change the sound or something??

 

http://www.tacomaworld.com/forum/performance-tuning/2012-diy-secondary-air-filter-removal.html

 

I have a 2.7L tacoma with an K&N filter kit on it, im looking to go back to stock since i need an enclosed filter fit to do mudding so i dont get water in the engine... wanna trade?