that's because your genuine 75,000km car with log books that showed up without log books was a 200,000km car and the speedo was tampered with.
as an aside I can't believe how many stupid people there are who really think Japanese do less kms than we do. FFS we don't drive to Sydney every day for work!
eg. a 75,000 R32 is 15 years old (on average). So you're telling me they only drove 5,000km a year? give me a break.