As far as i know, octane levels in fuels are standard throught the world. Octane is simply an additive, that lenthens the burn and lowers the temperature of the flame within the combustion chamber - why you have to run higher octane in higher compression engines i.e. under boost.
The difference between Japanese models and american models of specific types, well i haven't got a clue why we get the shitty low-horesepower ones
It's my belief we are improperly informed on this issue. After all, who else but north americans crave tire melting power the way we do? We're the perfect market ofr cars like that. Maybe these "Frankensteinish 400HP Type R's" are prototypes, not production cars.
Sorry to hear about Joey's car man, that's sucks guy
Oh, and as far as governments regulating maximum power to be produced by auto manufacturer's - that's f*cking bullsh*t