But there are more changes than just the engine next year: Significantly revised aerodynamics - wings, lower noses, lower front bulkheads. Also increased KERS capacity and to accommodate that and an increase in the minimum weight for the whole car etc... It's certainly going to be interesting to see how it all pans out.
You could well be right, I'm only going off reports such as these:
http://www.grandprix.com/ns/ns26086.html?
http://www.f1today.net/en/news/mercedes-to-have-100hp-advantage-in-2014?
But there are more changes than just the engine next year: Significantly revised aerodynamics - wings, lower noses, lower front bulkheads. Also increased KERS capacity and to accommodate that and an increase in the minimum weight for the whole car etc... It's certainly going to be interesting to see how it all pans out.