up to 300kmh in 28,9 secs seems realistic, make in real 31 secs, as gt2 is in real around 35 secs  (porsche offical in 33 secs)

So my question, got the eninge just an electronic update with more boost and an other exaust to reach this 620 hp, as the enigne specs seems to be the same as actuel gt2  (3,6 liter)

 

www.porsche.com/microsite/911gt2rs/flash/default.aspx