U can get a preformace one if u have money, check on ebay, there are sets u can get, filter costs about 15$ and the set would be aluminum, its said to give u more air, its 3 inch and some more HP. Its an investment, but alluminum doesnt rust so u can swap this ting to another car if anything. Its up to you.

Its basicly aluminum pipes with rubber hoses and rings. Its not that complicated.
If u cant afford (Like me

) it u can make something out of plastic pipes PVC, just visit home depot, if u heat that pipe with a torch it will shrink the tube down, so u can match ur intake or carubrator or w/e.

just plan it out. U can also use a "high performace" filter then, u can install it onto that setup.
U can buy rings, to put your systems togeather at homedepot too, same shit as regular pipes, its a ring with a screw on it that tightens.
Just make sure u reach the COLD air on the outside of the engine, or below or above the radiator, that will make sure u get better gas milage and HP.
U can also retrofit another cars system on urs, but its hard to tell which, it has to be simular size engine. I think it be eazeir to buy aluminum or even make ur own.
Goodluck