Rumor has it that GM will be coming out with a new version of the Duramax for 07...coded LMM. I've also read that the only difference between this engine and the LBZ might be the addition of a particulate filter.
I worked with a person that was deeply involved in the motor. Here are a few things that were mentioned to me.
1. New rod and main bearing retaining bolts
2. New head gaskets (Its a riveted design)
3. Intake air valve (like a gas throttle body???)
4. Using one wild looking tailpipe called a jet pump
5. 5 pulse injection per power stroke
6. Particulate filter
7. Grid heater and glow plugs. The reason behind the 1000 watt grid heater is to keep the engine warm during low load like idle and to aid engine warm up
8. I was also told it watches the amount of soot and if soot levels are too high the egine turns the mil light on and causes a limp home mode. This will be the biggest challange to us hot rodders. Most likely all brands go to somthing like this and we will all have to deal with it eventually.
9. Last thing was that the engine is designed to run on ultra low sulfer.
Hope this helps give you guys a idea of what to expect!
One more thing I would like to add. The throttle valve I mentioned earlier is supposed to actually throttle air like a gasser. Why would a diesel need it? Gm's EGR is supposedly much more effective under a vacuum than a open air plenum. I have not seen it (the detailed shots of the throttle valve) yet but from the pics I saw she looks a lot more crowded on top of the engine with all the grid heaters and stuff.
Just wanted to provide a little more detail on the subject.