SRegular prius usually gets better MPG. If you referring to topgear article which started this urban legend they've used Gen2 prius in combination with cold start in cold to get MPG lower and ran it for short distance. If it were a race distance result would be different.
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View my fuel log 2015 Mirage DE 1.2 manual: 46.4 mpg (US) ... 19.7 km/L ... 5.1 L/100 km ... 55.7 mpg (Imp)