Just my input of expeireance I had on my 04 Sierra gas truck.I installed a cold air tube and it came with a K/N filter,after about one year I took the filter off for a cleaning and boy was I shocked at the DUST inside the tube leading to the intake!!! The throttle valve was all covered in black soot which was probably dust passing over it.I wasn"t impressed,whats an engine worth today?but most don't worry about this because vehicles are traded in before lots of kms. are on them.So I said screw the K/N and installed a AMS nano filter, no dust! Check them out superior filter and it was DRY no oil to worry about as the other filter was always giving me a code(mass air).So there are lots out there and they give lots of promise but when you physically see there filtration performance you wonder how good they are? Thanks.