The new trend is for normal power levels with more gears so maybe 6l80e. GM put a whole crap load of money into it. The exhaust comes out of the heads into the lifter valley of the engine and into the turbos vs out exhaust manifolds, to an up pipe and into a turbo. Thats going to be cool to see. I would imagine it will also have a 14 bolt or bigger differential. However if i was GM i would be a little concerned about fuel prices for diesel. Nobody is buying them right now unless they have more money than sense. Insiders in the oil buisness around here are speculating that diesel prices will go back down. I dont think that will happen though i think that gas prices will go up to higher levels than diesel causing diesel to look less expensive