I just had lower control arms (and tie rods) replaced but still have a little shimmy. I am not at all sure whether lower control arms are the same as thrust arms. I did a complete front brake job (OEM rotors and Pagid pads) and was blaming un-even lug nut torque (or possible out-pf-round rotors) for the shimmy, which was less after an alignment.
I will also take this opportunity (I can hardly believe I'm doing this!) to give a thumbs-up to local dealer Critz. Reading the codes (to sort out a ABS thing that turned out to be a bad LR speed sensor) was only $65 and complete alignment was $129. After years of Critz=-bashing they seem to be coming around.
2000 528it (5-sp manual, M52TU engine, 220k miles and going strong) Bimmer #13!