I bought the Thule foot packs from Halfords, and then fitted the Halfords Aero bars - works fine, solid as a rock.
Bought 3 x bike carriers separately from ebay, and a Thule Roof Box from Halfords - so totally equipped.
HiI had a set of Thule aero bars and feet from myprevious carand went down to Halfords and bought new feet for the Q3 (753 Rapid system & 4027 kit). I use the old aero bars as they are only a few cms longer than the bar that Thule recommend.I carry two bikes often and the bars/feet make for a very secure fitting. The feet are rubberised and have not left any marks on the rails yet.However, they do not make use of the predrilled holes on the roof rails which makes lining them up slightly more time consuming (I just align the front edge of the foot to the front hole in the roof rail).I had a set of Audi bars for an A3 sportback (with the same style roof rails). The Audi bars made use of the predrilled holes, but I remember them being very high from the roof. The Thule's are much lower to the roof. Given the height of the Q3 and that putting bikes on is already a bit of a reach I'm glad I went for the lower Thule's. Of course the Q3 bars may not be as high and I bought my bars for the A3 in 2007 so the design may well have changed.