bell housing would be the easy part, and cheap. Budget around 500-600 (cheaper if you have access to a large mill and do it yourself) for something mint.. much like the hollinger to gtr housings, ive done a few custom ones like evo 6 to rwd etc and generally they cost me 200-300 trade.. and rated to same horsepower as the std cast items.
EDIT: Seen your latest post so ignore my post, i see you have the engine and gear already sorted.