To my understanding, German cars tend to have certain parts over engineered, and certain parts under-engineered. This achieve the unreliable you are talking about.
A garage that has a couple engineers would choose to use something already engineered (and most likely race proven) and use that as a basis for a better product. In doing so, they can save ALOT of R&D and focus more on their overall packaging.
VW insist on using W engine design, but the only advantage of this design is its compactness. So to make up for the power deflict, they slap on more turbos, this solve the power issue but create the heat issue. Then they slap on 3 radiators to cool the engine, 1 heat exchanger for the air to liquid intercoolers. Now they have solved both power and heat issue, leaving the ultimate left over.....weight.
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