The 90degree does hurt air flow.... The straighter is always better, but with the restrictions from the A/C box and whatnot, there is only so much you can do... I dont have the Explorer style 5.0 so Im not sure what you can do, but the best is probably a 45 degree, right? The trouble and expense you will go through is not gonna be worth the return, believe me.... I doubt you would actually "see" a difference at all. If it was a high hp supercharged or turbo application, you might be able to get some decent ponies out of it, but other than that I wouldnt mess with it. Keep it clean..... good luck and let us know....