Material of which that engine is made,matters alot.JZs are made up of Cast iron whereas UZ is of Aluminium.This makes it lighter.UZ weighs 460-470 lbs where as 2jzgte even being 3 liter weighs 594 lbs.
Just as an example GM's LS1 is 5.7 liter but is 460 lbs and smaller than 1UZ in dimensions.
2JZs are famous here because no one here tries to do something new,if someone has experienced 1jz he will always say 1jz Rocks, so will the others do.I still meet people who say "V8 bohot bara engine hai 1-J daal dete" where as v8 is smaller in size.
Its not that 1UZs are not modifiable, It can be taken to more than double of its power if just twin turbos are added on stock internals.
If 1UZ did not have any edge over 2JZ then the people who are swapping there JZ Supras with 1UZ would have never done it.You can find a good amount of Supras with 1uz!
And to correct you this engine not only came in Luxury Sedans but also in Lexus High performance GT coupe SC400/Toyota Celsior.People with GS400 claim beating stock 350zs,Mustang GTs,I have seen their videos too..Now you can well imagine if this engine does so well in a 1800kg Buffalo, what it will do in a relatively very light sports car like RX-8
RX-8's engine bay is big but has less space widthwise.Rotary is no doubt very small but its gearbox is almost double the size of 1UZ's gearbox.
ABS with RX8's ECU will work but the Cruise control and Traction control will not!
And Thanks for the wishes mate.
I'll take it to track for sure mate