Generally I would agree that any alternate filter appropriately selected would probably work fine. Overall, I understand the "BITOGyness" mantra ...
But I'll give you one solid reason why not:
You risk the consternation of warranty in case of a claim. Ford cannot outright deny a claim if you use a non-approved filter, but they can defer a claim until such investigation would show fault one way or another. And that could take MONTHS of stonewalling, etc. On top of that, most any filter maker will ALSO defer a warranty claim for not using an "approved" application, for their part of the investigation. So while all this is going on, and you're without a vehicle that you're still paying on, you get to sit and wonder if that "unapproved" venture was really worth it. If you select an alternate filter that is not approved for your application, it does not automatically infer that your warranty is void. But what it does is shift the burden of proof unto you, and away from them. So now you have to prove in litigation that your selection had merit; that your filter was properly spec'd. Do you have mounds of data and reams of papers to show that your gut-choice was a sound one? Because when they walk into the room, they are going to have all that, and lawyers, and that is after MONTHS of stalling and legal mumbo-jumbo via letters.
Now, I'm being specific to approved applications and not to brands. Any brand recommendation that you follow that is "approved" should suffice just fine with little risk. What I am saying is using a filter that is not approved by the OEM or the filter maker is a risk; a big risk to warranty. You may (not will, but may) succeed, but it would be after months and months of PITB efforts.
You need to read and understand the M/M act regarding warranties. They protect the warrantor just as much as they protect the warrantee. And case law over the years favors those who can show proof. That burden of proof shifts from them to you, once you venture off the reservation.
All because you were feeling a bit BITOGy.
Caveot Emptor.
