If your going the sensible route, grab an RB20 block and drop it in, will cost you f**k all and youll be back on the road sooner.
JIS have an engine, loom and ECU package for $1950, grab it, sell off the loom and ecu, sell your f**ked 20 for peanuts, some parts could be valuable to someone else.
Or JMS have an R32 front cut, no gearbox, low kays for $1500. Grab it, keep donk, sell parts, ??????, win.