Why did Volkswagen develop the W 16 engine for Bugatti Veyron instead of directly using the turbocharged V8 with the same horsepower of 1000?

V8 has strong turbocharging and large air intake! It runs fast, but its engine is not good, and the torque is not as big as that of W 16 engine! Engine W 16 is pure power, which is better than V8 in all aspects! V8 belongs to external force, while W 16 is pure power! So we need to develop W 16! The bigger the engine, the more powerful the machine!