Not sure how to set up a poll, thus this post regarding speculation on 2012 D4 US engine(s). Consistent with Audi experience some, including me, have concluded that Audi will increase the engine output on the second model year D4. Of course, the TDI would be wonderful, but all indications suggest that it will not make it to the US within the next year or two. However, that does not mean that Audi is not cognizant of an S Class output increase or the fact that the 7 Series has more grunt than the even upgraded 4.2, now in 372 bhp trim, that we have all grown to love in its various iterations. Although speculation, my guess is that the 2012 D4 will have a turbo charged or super charged 4 liter engine with output around 400 bhp and lb. ft. of torque. This will very probably not only make the D4 more competitive with its two main rivals, but that it will achieve more fuel efficiency as well.
I have driven the D4 and it is noticeably quicker than my 08 D3, but that may be gearing changes as well as the modest increase in bhp. The D4 is a phenomenal automobile. It would just be a bit better for me if it had more power.

I've been mulling this same issue over for the last several weeks. My current D3 lease expires this April, and under normal circumstances I would be ordering a D4 in January. Here's where my thinking is presently...

1.Hold off on ordering the car and wait to hear some confirmation regarding the engine "upgrade."

2.If Audi goes supercharged, I would likely wait until a 2012 MY order could be placed---but then I'd have to figure out some fill-in vehicle from May to September.

3.If they decide to turbocharge the engine, then I'd stick with the normally aspirated 4.2 V8. While I enjoyed the kick of the twin turbos on my previous '01 A6 and '04 Allroad, I don't miss the turbo lag versus the smoother takeoff of the 4.2 engine.

4.If nothing can be confirmed, well there's the A7 which could be fun.

At the end of the day, I'm not racing the car, and the upgraded 4.2 engine is powerful enough for my needs. The issue for me is that it would bug me to get the 2011 D4 and have it feel obsolete (in my mind at least) in less than a year. And yes, I am totally spoiled ;^)