well def not audi as they overcharge & dont use there heads just follow the book, so if you have a even the most minutely slight buckle from some knock they dont know how to compensate with adjustments, they just have settings & thats it so if you end up driving round in circles they say "well its set as per audi says so its correct" lol, lolFind a reputable tyre place not kwik fit with a decent system thats regularly calibrated, then test drive for any pulling to the side then go back for adjustments.
I would say £50 approx is fair, nowhere near the reported £200 from one audi dealership, but if you are doing suspension arent you getting it fitted or DIY cause fitters should have the system to do for you.
Yes its a tie rod bush.