One problem I have had with the roadster is the AM radio reception. I am a fan of talk radio, in particular KGO http://www.kgoam810.com . The KGO hosts have interesting discussions about current events without bashing people (e.g. Jon Stewart or Rush Limbaugh). I like to listen to NPR on occasion but they have too many interviews with obscure musicians about the meaning of life.
The reception in the Roadster is particularly bad near overhead power lines but also whenever the car is accelerating. The problem occurs because the wire to the electric motor is creating an magnetic field. Ampere’s circuital law describes how an electric current creates a magnetic field. In engineering school, the “right hand rule” helps you remember the direction of the current. Your right thumb is the direction of the current, and your fingers are the direction of the magnetic field.
Since the Tesla is an electric car, interference is being generated from the wire into the electric motor. Tesla discovered that this problem was more prevalent in the older roadsters than the newer ones. Turns out the newer ones have a thicker shield on the wire going into the electric motor. Tesla replaced my wire with a newer one but the problem is still there although about 50% reduced. The engineers are working on a better fix.