Question about Thule WingBar Edge 9595 M/L

No, the mounting bases are not included; you have to buy them separately and make sure you choose the right ones. But I don't think the product specified is suitable for mounting on a 2010 Audi A4 Avant anyway. When I look at the Audi's roof rails, the two bars seem to run almost parallel. I bought the WingBar Edge 9595 M/L for a Volvo V60 CC where the distance between the bars narrows towards the rear. I think that's why the product has the additional designation M/L, which should mean medium and large. One cross member is significantly shorter than the other and the correction margin is small. However, once you have found the carrier that fits the vehicle type and the mounting bases that match the railing, the Thule WingBar Edge is a perfect system!

I had to order separate rubber sockets for my Thule Wingbar, but I can't answer the question about availability because I drive a different type of vehicle.
However, I went exactly the same way when choosing: I entered the car type and then asked to see what was compatible and only then did I see what I liked.