remove manifold
plug oil drain and feed
plug water drain and feed
block the little dick pipe under the manifold (edit not 100% on this one)
fabricate inlet pipe to accept afm and throttle body.
thats pretty much it, since the new laws, I have deturboed 6 wrx's, and they make on average 60-80kw (remember these are 1200-1300kg cars), don't expect much more, and fuck me they are sloooooooow.