Quote Originally Posted by Rasmus View Post
Chad. That sucks man.

I do notice that you've a water-oil heat exchanger installed between the block and the oil-filter. My 2004 WRX doesn't have one of those. The oil filter just mates right to the block. Perhaps if you deleted the heat exchanger the header would fit?

Also without the heat exchanger you simplify your setup. YMMV. Let us know what you do.
Someone has been in there mucking about. Every turbo EJ has an oil cooler. FWIW it's also a particulate catcher also, when those motors go (which they do) it has to be replaced. Learned the hard way after not replacing one on a spun bearing and having to replace the engine again after 1,500 miles.