A few additional thoughts:
Regarding the horsepower figures, Jonny should have added a sentence or two about the fact that just about the worst kept secret in the automotive universe is that Porsche continually underestimates the performance figures of its sports cars. It is commonplace for independent sources like MT, CD, R&T, EVO, etc. to report zero to 60 times, for instance, several tenths of a second faster than those reported by Porsche. So, while it may be true that, literally translated, the horsepower figures, once converted to SAE standards, are lower than the number reported by Porsche, it is also likely that the pre-conversion number is possibly 5% lower than the engine's actual horsepower output.
Regarding the "rightsizing" of the engine and the negative implications of the additional weight of the turbos and required ducting, I also believe Jonny should have added some commentary about the fact that, in real world (i.e., stop and go) operation, there will likely be no actual reduction in emissions. The EU emission tests are known to be completely flawed as they "test" emissions when an engine is not running under stress and the turbos are not operating under significant boost. This, of course, negates the purpose of the turbos in the fist place. R&T did an excellent write up about this subject and is worth Googling.