They don't need PF, they need to pass the WLTP and the 6dTemp regulations. Almost all cars need the PF to pass the test, but PF itself is not mandatory.
For example 2019 Mazda MX5 6dTemp, no turbo, no PF. They manage it with a conventional NA engine. Ok small car, small engine.

Maybe for cars with a small production number there are excemptions and Porsche only need WLTP and Euro6c for the GT3 RS.


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daily (no fun): BMW 430d
for fun: Porsche Boxster GTS