[Perfectlap]

For 99% of buyers it will be fine. They won't even know the difference between NA and a Jetta/Golf sounding car, turbos have come a long way in the last decade. And on paper, the performance will be better than outgoing flat 6.
It will be a lot cheaper for VW to now lean on turbo power than to spend all the time and money to get more and more power out of a NA engine. The mid-engines have never been big volume movers, so VW wants to at least see higher margins on these cars.
I don't buy CAFE being the thrust of the move to turbos because those standards are fleet based and the four door Porsches do the heavy lifting in meeting CAFE. Also, the penalties for failing to meet CAFE are a literal drop in the bucket for a highly profitable company like Porsche on track to sell 200+k cars nearly all at enviable margins. Those penalties are more like loose change under the seats. These turbos are about creating cars with highly predictable profit margins that aren't catching fire forcing total recalls. With the turbo four they get profit, power and fairly quiet warranty periods.