To make it a turbo motor, and do it right, I estimate it would cost around $10 grand, but that's including about $1,000 to buy the car itself. With low compression pistons, a bigass turbo, good fuel and ignition 600 RWHP is very attainable. The 1UZFE comes in the LS400, the SC400, and something else, can't remember, but the one in the SC400 is the only one with the correct oil pan to clear the crossmember. The bellhousing to mate up to the R154 tranny has to be ordered from New Zealand. I still haven't figured out how to set up the electrical system and fuel management
Oh, and $500 is for a used motor. Which is fine, because these motors last ~400k miles if left stock and reasonably maintaned