What is the weight of a BMW s54 engine?

478 lbs / 217 kg

From the BMW brochure for the new M3:

"Weighing a mere 202 kg (445 lb), the V8 power unit featured in the new BMW M3 is a genuine lightweight. Even compared with the six-cylinder power unit in the former model, engine weight is down by some 15 kg or 33 lb."

445 + 33 = 478.