You should ask your self the question.. "What do I want to do with this car?"
If you just want to drive it, and occasionally go to the track be that auto cross or drag strip, then odds are you are more fond of the Celica supra's intent was in the first place; its a GT car *Grand Touring car, and being thus so its a performance oriented cruiser that is comfortable to drive, handles good, and has some grunt when you want it.
If a GT car is what you desire, then realistically the modern aluminum domestic V8's (typically GM) are the best choice and the reasons are as follows.
Fuel consumption VS horsepower figures; the modern domestic V8's are quite good. Many of them have cylinder canceling that turns that V8 into a 4cyl in under 250milli seconds, and back again in 250 milliseconds if you need it. Essentially there is not noticed delay in power if you actually want it.
Domestic V8's Heck even Toyota's V8 produce as much or more power stock than the JZ of your choice; they are reliable, and typically last as long as any NA JZ will.
Depending on what engine you go with, they can weigh from roughly the same (550LBS) to even weigh less than the JZ anything.. Also the modern domestic V8's produce more streetable power than any I6 engine can ever hope too all while being totally reliable and boost free meaning longer service life.
Sure the JZ is capable of 1000+ horsepower, but this comes at a monumental cost in actual dollars and reliability and service life. If you run the JZ turbo stock, then its only 320 HP, and a modern domestic V8 has that much power all day long with out boost, and all the reliability / service needs that go with boost of any kind.
If you want 1000+ horsepower, then drag strips are all you actually care about; in that case you are going to be burying money into a bottomless hole.. For the same $$$$ spent you can get more power more torque and longer service life out of a modern V8.
Last and easily my favorite part.. V8 sound, its just a beautiful noise.
The short story, is....... If you are going to do an engine swap, there is no such thing as a "bolt-in", so you may as well just go with a V8 that you will always be able to get parts and support for where that will not always be so with the JZ. Look no further than the 5 & 7M, they use to be semi supported, and no longer is this so very true. On the flip side regardless of the year it is possible to get parts for nearly any domestic V8, even very very very old ones.
I know, its not Toyota; but they are a lot less expensive to get working, there is more support and they produce way more power per dollar.
However if you are stuck on Toyota, and Toyota is all you will have in your car, then get a Toyota V8, you will be happy with it, they produce a lot of torque and that makes your car a lot more fun to drive.
Here is my brothers 5.0 Ford powered Toyota, it sounds fantastic, runs good, and has stupid power.
https://www.youtube.com/watch?v=-NSiHD3M0ao
https://www.youtube.com/watch?v=Lrxg2xTJG-U