I have a 2004 530i with the sport package, which includes front sport seats. If I sit in the driver's seat for more than 20 minutes at a time, the burning/nerve pinching sensation in my right butt cheek becomes so intolerable that I have to stop, get out and stretch. Needless to say, I have found this very disappointing in an otherwise great car. The only solution I can think of (short of selling the car!) is to try to install a used BMW "comfort" seat instead. With all my internet searching and discussions with used parts companies, I can not locate any available seats. I would like to hear from others if they have had similar pain issues, suggested solutions, knowledge of whether switching out a sport seat for a comfort seat is even possible and leads on how to find a used comfort seat.