Could it be clutch related? Thrust bearing going out? I know the thrust bearing is toast in my motor because it was from a 5 speed car.
John, I know it's not a bimmer, but I ran my old grand marquis essentially without any bearings for quite a long time. Noisy as hell, and I beat the crap out of it. I eventualy just swapped the motor....It never blew it apart. When the motor was disassembled, the crank looked like an old audio scroll and the bearings were paper thin. It had less than 10psi oil pressure at highway speeds
