The GT could have gone quicker....note the brake lights on Turns 10 (Fast) and 11 (Faster). Good places to go faster or at least hold speed and save time.
I have raced my (standard) GT against a (standard) 911 lightweight on a track. The GT demolished the 911 on the straights, but the 911 easily won in the corners.... It made for an enjoyable race. The twistier the circuit, the more advantage a Porsche would have.