Funny you should mention that.
I had not driven the SD in about two months and I was having some "withdrawal" symptoms from it.
So, I took it out on Sunday for a 30 mile drive and, as you would imagine, the stark contrasts to the SDL immediately are apparent:
1) Tighter road feel. Tighter front end. Tighter steering. Easier to maintain exact lane positioning.
2) More torque at part throttle settings. The SD just moves right out at lighter pedal positions when compared to the SDL.
3) Engine noise at highway speeds.
4) Lighter driver's door feel.
5) Back end at "proper" ride height. Better looking vehicle in profile.
6) More spring in the trunk lid. Pops right up.
Just reminds me how different the two of them are. I was very pleased to get back to driving the SD. Just have to get the damn head gasket changed.