GoHardGT3RS:

Such a water refilling requirement after so few laps would be a joke from Porsche.

Competitors' cars in this engine output league don't have this hassle (e.g. 488 GTB, 720S, Performante),

I don't know about the above but firnds McLaren 650 can only do 3 laps on Nordschleife then it needs refueling.