nothing wrong with using a k50 gearbox, its coming on 4 years in my daily with a k50,smallport 4age, 15" wheels, ive just snapped a axle when i changed to 15" wheels and that was because of the big increase in grip from wider tires,
k50: slight grinding of alloy knobs inside bellhousing to fit 4age flywheel, keeping cable clutch saves a lot of money, and drive shaft mods.
if you use ALL front wheel drive 4age parts then the price drops by half,
don't bother buying over priced RWD parts when you don't need them,
apart from rwd exhaust manifold of cause,
fwd motor with water pump, thermostat, alternator, fwd 4age flywheel and clutch cover, ae85 clutch disc, cut and shut smallport intake manifold(or big port if thats what you buy)
fwd ae92 fuel pump + cradle, it only needs slight extending and it drops into ae85 fuel tank,
ae85 fuel lines, generic inline EFI fuel filter $13, use the ae85 6mm fuel line as the feed and the 5mm as the return line. (no problems of starvation to date, over fueling if anything)
extended the wiring harness by 30cm to place it inside,
what i did was buy a good running smallport bolted the 3au engine mounts on and got someone to weld up my intake manifold, not a lot of effort for a car that's still not dead after countless midnight runs up the hills, JUST FAKING DIE ALREADY!! total cost was $1400 and crushed fingers,
as said before, better to buy one already converted if you cant spin a spanner, or you'll get ripped a new one for hours,