After reading the engine regs for 2014 I found some interesting things to note...I don't know if it was brought up before
Not only will the cars be allowed to have a motor/generator linked directly to the drive shaft of the ICE for KERS, they will also be allowed to have a motor/generator linked directly to the turbo shaft for KERS as well.
The KERS used to propel or brake the car cannot exceed 120kW or about 160hp. The batteries (or whatever stores the energy) can store a max of 5MJ. The KERS system can use a max of 4MJ per lap (max power output for 33 seconds), but can only recover a max of 2MJ per lap.
The car must drive only by the electric motor when in the pits.
The rear brake circuit can be electromechanically controlled.