Made a run from Kitchener to Port Elgin, Owen Sound and Collingwood and back with the Boxter yesterday and got a surprising 6.8L/100.
I didn't buy the car for that reason, but I'm happy with the result. Speeds were in the 80 to 90 range with the top down most of the time.
A week ago, I made a KW to Windsor at 125 kph average and got 7L/100.
In my more typical mix of driving I am getting about 8.2/100.