Older electronics and design, it's just that simple. Plus, you can pick up 2JZ-GE's for pretty cheap as they're far newer and likely to be in a junkyard (and were used in more cars).
1JZ is a waste these days. Years ago you used to be able to get a front clip for cheap and do a complete swap with the only real hard part being extending the wiring harness. These days, their front sump motors with hacked wiring harnesses and you end up spending the money on all the parts to make them work that you could have done on a 2J for the same price for a larger engine.
Not to mention the 2J is legal and part are easier to find (and if the engine is locally sourced, milage can be confirmed).
1JZ is a waste these days. Years ago you used to be able to get a front clip for cheap and do a complete swap with the only real hard part being extending the wiring harness. These days, their front sump motors with hacked wiring harnesses and you end up spending the money on all the parts to make them work that you could have done on a 2J for the same price for a larger engine.
Not to mention the 2J is legal and part are easier to find (and if the engine is locally sourced, milage can be confirmed).