OEM. From talking to BMW parts guys, springs obviously differ between, say, competition pkg or std suspension. They can also change based on the options you choose, i.e. premium stereo.
E92 M3 DCT - AiM EVO4 Data Logger / AiM SmartyCam HD / KW Competition 2-Way / OMP ARS Racing Seats / Brembo GT 365 / Pagid Yellow RS-29 / Rear Seats Delete