300kw 1uz, how much???

[quadcam boat]

I agree with the supercharger route. If you want power in a heavy vehicle, you couldn't go past supercharging - especially if you have the room to play with in an old holden. The lexus needs extra power down low in the rev range. I find it lacks power off the mark in my ski boat, especially compared to a 350 chev powered boat.
Go the blower!!