2004 BMW Z4 steering problems

For about the last five thousand miles, my steering has developed the dangerous steering condition( described by literally hundreds of owners in blogs and various postings-just do a search for "z4 steering problem") that exists in 2003-2005 BMW z4 roadsters. At first, the problem occurred only on very hot days (as described my many others). Now, it affects all aspects of driving, making the vehicle very difficult to control. Steering requires constant correction from left to right and does not return to center.

I have noticed on warm days the steering becomes sticky as if the power steering is coming on and off. This causes a over controlling of the car and makes it difficult to drive. I felt very unsafe. I took the car to BMW roadshow at memphis and was told the problem was the electric steering unit and will cost $4000 to repair. I researched the internet and was shocked at the number of complaints going back as far as 2009. I called BMW customer service and was told that it was not their problem.