Porsche says on Pirelli P-Zero Corsa N0 high performance tires the new GTS manages a 7:22 around the 'Ring. Without the optional tires, it manages a 7:26 which is still absurdly quick.
Is it believable that tires shave 4 seconds? Absolutely. It is believable the 911 GTS is a quicker track car than a Carrera GT? Absolutely not.
7:22 is exactly the time for the previous generation Viper ACR in a test by Dodge which happened to be an overall production car record at the time. 7:22 is 2 seconds quicker than the 997 GT2 RS as tested by Sport Auto.
Let's just say we want proof.