PRmustang

I have an 80 mm Pro-m Maf that's supposed to moun in the stock airbox, or so it's supposed to. Problem is, I can't find a way to fit the maf and air filter in the stock airbox properly. It doesn't bolt on right, so I just ended using the airbox over the Pro-m filter loosely, because I can't bolt it the way it's supposed to go in. The thing works, it just doesn't look right. Did that make sense?[:@]Has any of you bought the same setup that can tell me how to bolt it up right?? The car is a 99 mustang gt, by the way...

Any help is appreciated!!!!