@ Adam R - Audi will get the car sorted. It is just a question of time. Remember that in 2014 , Porsche only got the first generation 919 really sorted out by the end of the season. Yes, I know there are big differences between a new team with a new car and Audi, but it should be noted that this new Audi (car) is a very different concept and even Audi (as a team) are undergoing quite a few personnel changes. What I'm not sure of is whether it will be an all conquering car, but I have little doubt that it will give both Toyota and Porsche a very, very hard time.

Yes, 2017 will be a boring year (in terms of new cars), and another reason for Porsche to be concerned about next year. They will have essentially a 4 year old car, whilst both Toyota and Audi will have 2 year old cars.

As for the 919 reaching its end: I don't think Porsche have any choice. Racing cars (especially at that level) have very short life spans. The rate of development is so fast that Teams have no choice but to introduce new cars every 2/3 years at most.