The 1jzget came in the soarer version of our car, a very high potential turbo charged 2.5. Alot of guys in austrillia seem to favor this engine, the 2jzge came in the sc300 and non turbo supra here in the US, the turbo supra recieved a 2jzget which was a turbo verison of the 2jzge ( obviously there are some other differences internally and externally but basically the same )
The basic idea behind the swapping to the 1jzget is getting as much power as possible and at the same time lightening up the car, given a 2jzget would do the job to power wise at least, and I noticed a couple guys on here have just turboed the stock 2jzge that came in the sc300, it comes down to a matter of preference and money really