dont put jap **** in a good aussie car... go with the 5ltr
You do know the potential of a 1JZ/2JZ motor compared to our dinosaur V8 5L. There is no comparison in stock form the jap motors are superior. And the gap only widens once you start modding each motor dollar for dollar.
Lets compare these motors stock. Jap motors are all limited to 206KW on paper over some stupid agreement all the manufacturers decided, but a 1JZ motor has roughly 215KW while a 2JZ has 240KW stock.
Toyota 1JZ
Displacement: 2491cc
Power: 206KW at 6200rpm (Really 215KW)
Torque: 362nm at 4800rpm
Toyota 2JZ
Displacement: 2997cc
Power: 206KW at 5600rpm (Really 240KW)
Torque: 431nm at 3600rpm
Holden 304 V8 (VN/VP/VR)
Displacement: 4987cc
Power: 165KW at 4400rpm
Torque: 385nm at 3600rpm
If you have the money for a 1JZ/2JZ conversion do that its different, gives you better fuel economoy better performance, a much smoother engine, unlimited potential for mods. To decide between a 1JZ or 2JZ I will personally go for the 1JZ as a 1JZ front cut can be purchased for under $3000 while a 2JZ can go up to around $6000-$7000.
If you get a 1JZ installed in your commodore, if you leave it stock it will still out run a Holden SS Commodore Gen 3 5.7L, it only runs 8psi stock boost.
Buy a full exhaust system from turbo back, CAI, Pod Filter, Front Mount, LSD Diff, and get it dyno tuned and boost it to around 12-14psi which is still a safe level and you will be seeing 220KW at the wheels or roughly 270-300KW at the flywheel. These motors dont need to be strengthened until you reach 350KW at the wheels, thats how well built they are internally.
Not many cars will beat you on the road, and you will be seeing mid to low 12's on street tyres. I reckon the whole conversion will cost you less than $10000 with spare change.