I was in Autozone the other day and was looking at the K&N air filters, and wondered two things. First is there really any reason to get one, and does the filter for the 2k2 work for the 2k3 (the computer did not have a model listed for the 2k3)?

Thanks!

 

I bought a K&N drop in filter and didn't really notice a difference. But they pretty much last forever so it will be the last one you have to buy and you only need to clean and re oil them once every 50,000 miles. I did notice a power increase when I bought a Stillen intake with a K@N filter and it sounds awesome when you floor it.

 

The drop in filter will give you no noticable increases. You will have to buy a new Intake which is super easy to install.

 

On an older car (1990 Mazda 626, non-turbo) I had it did make quite a difference, especially in the top-end. (3-5K RPM, 4.5K is about as far as I took that old SOHC engine)
The stock 5th gen Maxima air induction system looks restrictive enough (especially the inlet to the air cleaner) that a high-flow filter might not be the bottleneck, thus an intake should improve things.

BTW, if you change the intake, is it possible to have a Nissan dealership hook up the CONSULT-II and reprogram the ECU to account for it? I'm a bit weary of making mods to my engine just because of the possibility of running too lean... a coworker had some pinging in his SE-R Spec V after changing his intake, so it caught my attention.

 

I had my 1989 Maxima go 90mph on a freeway last weekend for 3 straight hours, brought it to 6k rpm too. Go Nissan!

And I do not think that hi-flow intakes need ECU reprogramming, you should be fine, but watch out for over-oiled filter that can damage your MAF.