A battery and a starter motor. No intention of modifying it. Although I'd be intrigued to see what it would be like stripped to death, on coilovers and on a track. But M3s are getting so cheap....there's no point!
Or 'those' people who build a Saturn 5 rocket in their shed....but get all bat shit crazy when 'forum geeks' ask for pictures and details.
Because they are serial bullshitters, living in an imaginary dreamworld.