Ls 400 / Crown Engine Transplant - Swap

[Customax]

I own a 1997 Toyota Crown Royal Salon 3.0L, I believe Ls400 and the jzs151 is based on more or less the same car.

Importantly for me they share some of the same engines and gearboxes.'

Engine in the car is the 2jz-ge 220hp, non turbo supra engine. other model came with the ls400 V8 4l engine.

** My goal with the engine swap is to get a car with between 300 - 400hp running on LPG (GAS) Today I have this installed.

Engines I am considering is

1. 2jz-gte Turbo supra engine

2. 1jz-gte 2.5l turbo

3. 3UZ-FE (LS 430 engine)

4. 2GR-FSE (lexus is350)

1) Any body done similar swaps with or without LPG?

2) Engines here are sold with gearbox and ECU, will all these engines fit into engine bay?

3) Will I get all instruments to work?

4) What engine should I go with?

Anybody how experience with turbo engines on LPG, read somewhere I need a spesial type or my car would be a possible gas bomb?