I have upgraded form the A8L to the S8. Most of optional features are standard. Suspension firmer and tail shorter. Steering better calibrated. The car is clinical, technical and takes time to warm to it. S550 4-matic has superior steering but S550 has poor interior, poor iPod integration and weak navigation. AWD is superb even in A8. Superb driving in snow, ice. Excellent traction. Rear space is tighter than A8 and S550, but tail handles better.