Yeah, the 155mph limit was like the 'gentleman's' agreement in Japan of not creating cars with more than 276hp (combined with the speed limiter):
When I was a kid, my favourite game on Playstation 1 was Gran Turismo. Watch this video on YouTube One thing that always used to confuse me, however, was the fact that so many cars in that game all showed a power figure of 276hp: But why are Japanese cars limited to 276hp/280ps (or near ... Read...
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But it got a bit silly when car manufacturers would say officially they were 276hp, were in reality they were higher.