The KERS charges under braking. Drivers do plenty of heavy braking on the warm up lap already to get their brakes warm. We probably wont see much of a different behavior.
The diffusers are certainly worth a lot. What bugs me a little is that we have to wait a month for a ruling on them. Meaning those with them don't know weather to stop using them yet, and those without them don't know weather to incorporate them in the design or not. A lot of money and time could go down the drain for teams over this one. Why can't they have said "yes" or "no" already so everyone knows where they stand and what they should do.
As has been said before, the FIA could have sorted this issue weeks ago, and it would certainly fit in with their mantra of keeping costs down etc., but it's a good way to create division amongst the teams (i.e. FOTA).
Divide et impera.
Ayrton Senna: WDC 1988,
1989, 1990, 1991
McLaren: WCC 1974, 1984, 1985, 1988, 1989, 1990, 1991, 1998,
1999, 2007McLaren: WDC 1974, 1976, 1984, 1985, 1986, 1988, 1989, 1990, 1991, 1998, 1999, 2008