Aftermarket 4" air box?

I need an air box with a 4" opening to the maf or pipe. Right now i have a carboard template that is serving as my air box.

Yes i need one I cant just run a filter, air turbulence is throwing off the MAF, it needs to be controled.

I sent an e-mail to injen about having a 4 in air box. not sure if they make anything that big.

its a draw through setup in the fender going down toward the front bumper. Right now I have a cone filter and used a box from my 10w-30 oil. Just cut it back a bit and taped it up nice, cut a hole on the side of the box by the fender to let air in.

I was looking in the rag shop at from 1/4in Styrofoam. sheet metal + rivet gun might be the best approach though. Id like to have some kind of latching assembly so i can take it off when i need to.