On my last 2 vehicles, I've replaced the stock paper filter with K&N filters keeping the original airbox. With that, I've have seen a little bit of increase in low end torque. I know that because there is a little knoll on the way to my house and when I drive 30 miles an hour, I had to downshift my civic from 4th to 3rd (well, didn't really need to but I could feel a little bit of hesitation). With the K&N in place I don't need to downshift anymore at that spot. I haven't seen any improvements on gas mileage. On my Jeep YJ that I had, I did the same thing and I noticed I didn't have to downshift as much as well. So I know they do make a little bit of improvement. Now it`s debatable if the price is worth it.

My question is to those who have run both a K&N filter in the original airbox and also replaced the airbox with an intake kit (obviously not at the same time). Did you feel the difference was greater with the intake than with just the filter?

The reason I ask is that in Canada, the filter sells for 100$CDN and the intake for $300. I would not think it's 3 times better.

Opinions?