lower arm bush? What is the mileage of your tyre now? How long has this been happening?
Some tyre when age and wear, it will not be perfect balance. My CSC3 regardless of all work done in MPS using BMW ori rim & ori size, shake like hell after 150km/h when I last did my rotation, till I dare not speed above 140km/h. When I swap back the rear tyre back up, it's gone!