I am going through the same thing right now with my 535i. Been towed in 3 times in the last 4 weeks, and been in for engine problems and electrical problems 6 times in one year. Had fuel pump replaced. They had more fuel pump issues. Then had fuel injectors replaced. Also have had electrical problems. I am suppose to hear from BMW tomorrow as to what is happening. If they do a trade, I am hoping to get into the X5. I just hope I don't have the same problems all over again.