Just tested the new MAF, but exactly same Behaviour

I did disconect the battery before switching mafs and also did the reset procedure before starting the engine.

I also measure acceleration randomly on a 3rd gear 60-160 kmh at the highway (late night when safe and noone is around) and can tell you I lost 0,5 sec during last couple months. I was reaching 9,7 sec. And now its about 10,3 sec

I did typical maintenance (oil, filters, etc) a trackday and little more on the car during these three months

Any ideas what should I try next?

 

some update and new info after several weeks of trials and changes.

I have changed MAF and AOS for new ones
We check for leaks with no luck.
Switched back to fully standard plenum and intake

Kept testing and no significant improvements

We tested with wide band external sensor with surprising results:

The car ran perfect AFR at intermediate gas pedal positions
When pushed hard (WOT) the car was super reach from low to mid revs (5.500rpm) the progresively went to slightly lean at max revs.

I'm also getting P1115 & P1119 fault codes when pushed hard but no CHECK ENGINE LIGHT.

I asked help to porsche enthusiast around and none could understand the case.

Might it be something weird on the fuel line? Fuel pressure regulator, injectors?

Any help is highly appreciatted as I'm getting stacked