Although Nissan has not released any written statements commenting on Porsche's claim that it cheated when recording the 7:29  lap time around the  Nürburgring Nordschleife, one spokesperson did comment on the accusation:

Nissan is "..not going to get into a war of words with Porsche. The final word from us is that it was done on absolutely standard tires which are available to customers in the showroom. They're not trick tires – absolutely standard tires, normal road tires. The GT-R comes with Bridgestone and Goodyear (Dunlop). One tire gives slightly better times around the 'Ring. We did it on Dunlop. They're available with the car." said Neil Reeve, a Nissan spokeperson, at the Paris Motor Show.

[via StreetDrift]