A6 - Front-end Vibration Braking Above 30 MPH
 

I have a 2011 A6 3.0L with 130,000 miles on it. I love my A6, but have been plagued with vibration issues in the front-end when braking. First it was warped rotors. Then something to do with tie rods? Now the vibration is back and braking doesn't feel safe (sometimes) at highway speeds. I'm tired of different diagnoses and having this recurring problem.

Short of going to my local Audi dealer and spending a small fortune to have this properly diagnosed and fixed, can anybody help with additional suggestions, questions to ask, etc?

Thanks in advance.