My wife has a long term back problem, so she is very sensitive to poor car seats. She finds it most comfortable to have the seat squabs almost tipping forward (Can't stand that myself, I have the squabs in a much more normal mode).
I put 1 inch blocks under the rear of the seat runners. My wife now finds the X3 Msport with Sports Seats to be the most comfortable car we have had for many years. Whilst there is sufficient squab tilt range that I am also very happy
PS. I also had to block up the previous Toyota, Honda Accord and BMW 320D by about the same amounts: So this is her problem, not a BMW problem, but the solution might help others.