I sell MAC cold air intakes myself. If you are interested I will sell you this intake for the price $169.50 + $0.00 shipping (special recession pricing). If I am not mistaken this is the only cold air intake available- not even MAC has them at this moment.
MAC calls me on all thier Explorer units and 2 months ago I purchased all the 5.0L kits they were releasing. If I am not mistaken (could be wrong here) even E.Express is out of these. I only have 1 left.
As far as making your own intake, ehhh that could be a toss up. Usually ill fitment turbulant air and bad design make for less than stellar results. Please keep in mind that these companies who make cold air intake have flow benches and also test each unit so the kit doesn't provide ill driveability or everything you just saved will have to now be spend getting the vehicle tuned just to drive correctly. Although most that have a cold air end up with tuning anyway. Either way have fun with you future performance endeavors. Glad you are on here!
Email me if intersted. BTW-the MAC kits are great kits, I have never had a complaint out of them.-j