They also refer to the dfi as "motorsports derived" in the s literature.
I think the gt3 will be a dfi 3.8 just like the s. Why wouldn't they?

 

For what it's worth, this writeup claims: "it will use the 991's 3.8-liter unit modified by Porsche Motorsport's division to deliver somewhere between 450 and 500 horses."

I do believe these pics are pretty new, though:

http://carscoop.blogspot.com/2012/08...e-911-gt3.html

 

I want to believe some rumors more than others.....