22+ UEH Compatibility

As the title states I have a 22 wrx and am looking to get some UEH to get me some sweet sweet subi rumble. I see all these UEH for the old 15-21 platform but it does not exactly show that it won't fit on a 22 platform. Will it or is it that much different? And why the heck does a header cost almost as much as I paid for my entire catback exhaust? It's a bit crazy me thinks 🤔