Conor
"Bob's your Uncle"
I have a full K&N intake for sale for a 5.3L NNBS. This came off of my 2007 LTZ. I have had it for about 6 months or so, put maybe 7K miles on it. Intake is in perfect condition and comes with all pieces and I will clean and oil the filter before its sold. Comes with full heat shield. Adds a nice bit of power, sounds great and helps with fuel mileage if you can manage to keep your foot out of the throttle.
http://www.knfilters.com/cold_air_intakes.htm
http://www.knfilters.com/cold_air_intakes.htm