We are currently proud owners of the Sleep Number 7000, which is now called the P7 i think. This bed is the answer to our prayers! We have gone through 2 mattress sets in the past 5 years. I don't know why, but our matressess always seemed to sag in the middle by the end of the year. We've even had what was supposed to be a top notch set. We would wake up with crippling back pain and stiff necks. The Sleep Number bed has made a huge difference! I have suffered a few lower back injuries and traditional mattresses always left me feeling like I was just ran over by a frieght truck. When I get up in...