I doubt anybody would touch KERS through turn 8 or after it, or anywhere at high speed except in desparation, it just negates the advantage of the extra power when resistances are so much higher.
I was briefly amazed at the McLaren KERS system apparently contradicting the laws of physics as Kovalainen blasted away from Barrichello at the end of the back straight, until Barrichello confirmed later he had lost 7th gear :smile:
Thinking about it, I can see McLaren struggling through turn 8 with their system, if the batteries are outboard as the Monaco photos suggest, and the adverse effect on high speed aerodynamic downforce they are suffering.
This seems to be confirmed, Hamilton said after the race that he was losing up to half a second through turn 8 as the car seemed too heavy and was refusing to turn. He didn't attribute this to KERS, but it supports my prediction in the post above.