http://www.autosport.com/news/report.php/id/116449
McLaren's Ron Dennis says customer F1 teams can't win titles
Reflecting on his team's campaign as a Mercedes customer, McLaren's Group CEO said: "The one thing that jumps at you, if you look at all the qualifications this year, is the time difference between the Mercedes-Benz works team and other teams.
"And by and large it is always in excess of one second, putting aside the pace that they can generate in a grand prix when they are on their back foot.
"My opinion, and it is an opinion held by many people within our organisation, is that you have no chance of winning the world championship if you are not receiving the best engines from whoever is manufacturing your engines.
"And a modern grand prix engine at this moment in time is not about sheer power, it is about how you harvest the energy, it is about how you store the energy."
He added: "Effectively, if you don't have the control of that process, meaning access to source code, then you are not going to be able to stabilise your car in the entry to corners etc., and you lose lots of lap time.
"Even though you have the same brand of engine that does not mean you have the ability to optimise the engine."