Mainly the reason when fitting externally braided hoses being amazed by the difference in brake feel (no - it's because the fluid has been changed)
+1
I tend to go for taking each front caliper off, pads out, pump the pistons out a fair bit (not too far!) Then hold the brake pedal down to seal the top end of the system. Last step is to open each bleed screw in turn on the caliper and press the pistons back to force the old fluid out the bleed screw. Sounds complicated but is really easy on the M3W, though not quite as easy as on a race bike.
