Not sure what you mean by the Aero Thule Bars, but the Q5 comes with a pair of bars which fit the roof rails. These should be used because they have connectors that fit into the rails and tell the Q5 to alter the ESP program to compensate for a roof load.
If you have a part number of the Thule bars I can look them up, but as I said above if they are only the bars, Audi specifically warn against using anything other than those they supply.