SD325i. You can safely go to 5000-7500 miles on the
original oil from the factory for your first change. Do
not use castrol syntec 5w30 or Mobil 1 5w30/10w30
for these oils DO NOT meet the BMW long life A3 specs.
Use either the BMW 5w30 A3 rated oil or like what
white 330 ci stated, Mobil 1 0w40. Also, do not go
by the 15000 mile (25000 km) interval. No synthetic
will last that long and protec your engine.
My own $0.02 (cnd.) worth.