Good, my worst worry is getting the front bumper of my S4 lined up spot on after fitting the sensors, Audi use a couple of adjustable jacks that need backed off before the bumper can be removed. Just an observation, Audi claim to provide maybe three colours of tophat seal thing, depending on which colour the body colour is, my wife's VW Polo 1.2TSI 110PS SEL, bought new in August 2015, is silver and has black tophat seals on the sensors, as do other cars from at least VW, I did not notice that until I started checking up on part numbers for making my kit up! I think that all VW group bumpers, and maybe other marques, have these positions marked in them, which is handy. Plan thinking behind the hole cutter I bought is, as it cuts in from the painted surface, it draws in slightly the area round the edge of the holes, so there is no "bare" bumper material showing, and that coupled with the tophat, or stepped seals, leaves the installation looking like factory fit - time will tell!
Now that you mentioned it, after committing myself to retro fitting front sensors to my S4, I've noticed that what initially looked like a perfectly flush mounted set of sensors on my wife's Polo, on closer examination all four are not perfect - but I'd think that I am too lazy to take the bumper off to check if the sensors are clipped fully into their mountings.
