Remko

As above. Would STI exhaust manifold/headers and uppipe fit a WRX? If yes - for which models does this count? I need a new/other manifold/header (whatever you call it) for my 2001 WRX and if STI qualified items would fit this would give me a far larger range of items to choose from.
Thanks for reading.

Oh, and sorry for noobish question. Only recently became Subaru owner and had planned learning about it by reading a lot but because of more faulty parts than I was aware off things snowballed.