its not a cheap car to build. thats why many people walk away. problem is parts are sold out before they reach pk.
mine already costed me many times its purchase price, a few parts are in pipeline on way to pk.
my source was ebay plus shipping and handling and other charges.
if yr going to swap 20v, the problem of air intake for 4rth cylinder is going to be bit exp to solve,as the engine donest fit without some mods.
if you can build a 16v turbo, thats bit technical to drive, owners of turbo rwd can explain better what happens when boost kicks in. but to find rwd version of 4age isnt easy. markets have 4age 16v but you need to run them on map with open itbs.
ideally this car runs best on nonturbo(n/a) engine, the higher the compression is, quicker responce you get.
first step for you to get bodywork done, swap an engine,
you have 4age, 3sge, and 1jz choice. but all require modifications. there is a 3sfe also, but i havent driven it. so i dont know much abt it, that does have torque.
you will need help from pwlers in khi who have experience of swap work, get in touch with senior members there