I can't remember specifics off the top of my head but it seems Ford just changed little things that make it enough for parts not to match up. Something I hadn't mentioned before is a lot of the aftermarket companies don't have good return policies(for good reason)therefore its a little un-nerving spending $300(hypothetical) on a header that you can't return and then find out once you get the manifold off there are two studs in the wrong spot. Then you have to try and sell it to an individual and potentially lose money on a brand new uninstalled part. Gets expensive and annoying very quickly. This is just an example but you get the idea. One thing I know for sure is different is the engine bay/hood size/arrangement make fitting intakes a problem. Just a few things I can think of. IIRC one guy bought a Focus JBA Header and all it required was a new CAT flange. Its little things like that which aren't always easily fixed by welding a new flange on(as with the latter example). I think maybe Ford did it on purpose.
It's all a conspiracy. :rolleyes:
