Dan, RE: 2.0L vs. 2.+L. This may not apply to Honda in this case, but many other cars are kept at 2.0L or lower so that they can compete in certain race classes. In World Rally Championship racing, the maximum displacement for an engine is 2.0L so that's why the Subaru WRX STi is a 2.0L in Europe and Japan, but is a 2.5L in the USA. (This also explains many 2.0L or smaller offerings from Ford in its Focus, VW in its 1.8L Turbo line, etc. etc.)

Another reason is fuel economy. Gas is a lot cheaper in the US, so we can sell large trucks with V-10's in them. But where fuel is moe expensive, it makes sense to use a high rev'ing small engine because when that engine is kept at low RPM's, you can get good fuel economy. Spin it fast, and you have power.

Finally, in Japan, it's very common for car makers to falsely underestimate their horse power ratings to keep insurance ratings low (US car makers did this in the 70's). 280hp seems to be the "magic number" over there, but many cars listed at that make far more. Displacement or engine size might also be a factor in insurance rates, I'm not sure.