Madness, anythings possible if you have an unlimited budget
The 4wd chassis have different front chassis rails to accomodate the front drive shaft access to the front wheel hubs so add in a matter of body building. Supply of parts and fitting I dont think somewhere in the 20k area isnt far fetched. eng box clutch rear cradle brakes efi wire then body wire body mods bulk labour hrs, banannas
as for help booster and jimi giving a splash of realism should be taken as a gift, as for "not having money for gtr etc this conversion would be a "all at once" deal, one hard $ hit. Id want to be clear I wanted to do this before asking for a quote as it may take the supplier a few hrs to write up accuratley
have fun