Seat creaking fixed on driver's side was the seat bracket (scissor bracket) hope that helps. Seems the passenger side is also doing it but much less.
2013 BMW Alpina B7x SWB Alpina Blue, Dinantronics Stage 2 600hp, 612lb/ft
2016 BMW X5M Long Beach Blue, M Perf parts, RKP diffuser, Dinantronics Stage 1
awaiting 2017 M770i (to replace the B7)