I realise this is an old thread, but I've only just become the second owner of a 2007 120i E87. Lovely car.
This one has the "sports" seat with adjustable thigh support and and a little compressor pump in the seat (switch on outside of seatbase). However, acticating the pump pushes the SIDE/lateral supports in tight against my body without providing any movement in the lumbar region.
Looking at the diagram at RealOEM
shows a pneumatic lumbar cushion but none in the lateral "Lordosis" pads.
Could this be a malfunction of the lumbar cushion - or was there an option for just lateral cushions?
I have a bad back and it starts aching after a very short time without any lumbar support at all....