So one week into B9 RS4 ownership and a few miles under the wheels the vehicle is growing on me - I can admit now that I seriously toyed with trying to undo the deal and get the previous RSQ3 back, missing the drama of the thing whilst not embracing the enormous capability of it's replacement. Now I 'get' the B9 RS4 - it is a remarkably competent vehicle, the Sportdiff seems to add a capability to almost spit the car out of corners with a noticeable rear drive bias with DRC keeping everything flat which finds one looking for cross country routes with bends in. DRC is really subtle - it's only when one does things that would normally compress the suspension (hard acceleration, braking or cornering) that the feature makes it's presence felt - or rather it doesn't but provides the confidence to press on harder than ever. Love it! The agility of the RS4 is such that it feels like it's the same length as a TT, amazing. The one area I'm not massively impressed with is the B&O 3D sound system, which seems to lack bass and volume - I wonder if it's just mine or representative of the range. I've had B&Os in a couple of SQ5s and it was fine...a trip to a dealer to double-check I think.