Hi is it me or is this normal, i purchased i full kit for replacing the stock HU..The aftermarket mounting cage is universal and stated as 110mm for a 2011 A3 however when i measure the aperture for the new cage to go in the height is fine(110mm) it's the width that i find is a issue ,the aperture is 180mm wide and the after market cage is 184mm andi can tell that cage was not going in ...Next was the cage that came with the unit and that was slighltly smaller at 182 mm but more rigid so i persevered with this one but really struggled getting it in to the point were it sat flush and couldn't go any further ,thinking i was fine i then put the new unit in and again i strugled getting it in and after fitting i was not happy as it was just not sitting as it should and you could clearly see that the cage was just to tight ,anyway its coming out if i can get it out and i am going to see if i can get a cage at 180mm as anyone else found this a issue as to me something at 184mm will not fit in a aperture of 180mm ..