I've been quoted $6500 to get an rb20det conversion done by a shop that's done it before, including supply of the engine (+ new belts, seals, plugs, water pump), custom sump/pickup, intercooler and piping, exhaust, mod plate...
Based on the research I've done I don't think I could do all that myself for less than $5k... I guess that's something else to think about.