I did a write-up on the old D2 -
http://www.volvoforums.org.uk/showthread.php?t=216917 -which I could compare to my D3. I didn't like it much.
The new D2 is a new VEA 2l engine with 120bhp, I'm not sure if demonstrators for them are even available yet as it's only just come out.
Personally, I'd go for the D3 with 150bhp - it's still under 110g - and will be much better suited to the size of car.