Thanks for the input guys.
Yes, it seems that after they have replaced the rotors/pad, it is fine until ~1k to ~2k miles (1-2 months), then the vibration in the steering wheel while braking between 45-30mph is felt gradually increasing from then on.
I currently have 46k miles on the car. Main warranty just expired Feb 13th this year and is now on CPO warranty.
When I bring it back tomorrow morning, I will mention the arm bushings and see what they say.
2008 White/Cream 550i - SOLD
Sports, Navigation, Comfort Access, Sports Automatic Transmission, Heated Front Seats, Logic7, Sirius Sat, USB/Ipod, Auto Rear Sunshade.
LED interior, license plate and side markers lights.
Black powercoated OEM wheels, matte black kidney grills, shadowline rear "550i" emblems.
Reus Audio System