the tube.. anything.. i would recommend the Blitz Sus-Power filter.. cone filter that is constructed with stainless steel.. even the mesh is stainless steel.. easy to clean.. run warm water.. don't have to buy a cleaner...
<a target="_blank" href=http://www.blitz-na.com/North_America.html>http://www.blitz-na.com/North_America.html</a>
it is a universal filter... the adapter and fitting you have to get on your own... reason why i got this.. it is for life.. the cotton cones (K&N) you have to change when it get too dirty.. yeah you can get a cotton cleaner.. but it can only clean so much.. plus it is messy.. then you have to wait for it to dry.. and when you dry it the cotton starts to shrink.. this one you just run underwater.. shake it then put it back on.. plus the stainless steal design.. I think they run like $120? I dunno I got mine for free... yeah sounds expensive.. but you have it for life and don't have to pay extra for cleaning and oiling kit.. plus it has better increase of airflow then any filter out in the market.. or call blitz @ 714-777-9766
plus I made my own heat shield made up of Heating Ducts sheets
oh you have to click on the <a href="http://www.blitz-na.com/NA_ProductsSusUniversalFil.html">SUS-Universal filters</a href>.... those prices are for 2 filters for the supras and stuff.... the universals are $ 120
oh damn i need to show you guys my ram air set up. i have a ractive air filter then got some 3 inch flexable piping all the way down to the front bumper its cool on the freeway lol ill get a pic soon =) INACOMA saw it