Exactly, no replacement for displacement... unless you have an extra turbo or two :evil2:
There are still a dozen scenarios with the 6 cylinders, you could do a 2JZ-GE NA-T on 7M-GTE electronics, or a 2JZ-GTE with stock twins, a 2JZ-GTE with a big single, a 1.5JZ, a 7M with a big bad single...