America's testing procedures for cars is one of the toughest, The RX8 in Japan achieves its intended output mainly because testing is more lenient there.

So you either blame the car's engineering or America, I'd go with the former.

And Americans care too much about HP number on cars...

And brands if you ask me... cant believe people there wont pay over 30k for a "Toyota" but splurge 60k on a "Lexus". Or Acura, or Infiniti, thats just over-rated brands.
Bring that Lexus to Japan and no Japanese would pay double for a rebranded "Toyota".

It all boils down to intepretation of the spec, and marketing habit...

It was an honest mistake by Mazda for not retesting the car with the US rules, as simple as that. This statement;

"It had a high horsepower rating. But when drivers got inside, they discovered weak low-end torque, meaning that the rocket-like acceleration they'd expected was missing."

Thats just so bloody exaggerated... 250, or 230, or even 200 hp, you wont feel anything "rocket-like" from 50 hp difference.

I suppose that is why last week Toyota launched the Lexus brand in Japan? Also, Japanese sure seem to be happy to buy BMW's with their inflated price tags.

Americans pay too much attention to HP when what they really want is a lot of low end torque. BTW Honda/Toyota != Asians. That's two companies from one country. They don't represent Japan or Asia as a whole.

What about Nissan I don't see them reducing horsepower claims.