Forget what you know about the Porsche.

Note: Negative toe might still work in the qualifying environment. But all my setups will for now utilize positive or only slightly negative toe as I expect it to be the more sustainable solution.

Overall the new Porsche needs less steering as before and it's easy to turn too much.
Be careful on turn in. The tires likely need half a turn or more to build temperature on the surface and they are more snappy on entry when still cold. You can get them warm more equally by reducing camber and going for more positive toe. This will cost lap time in general, but might gain you time if the car is unrealiable on corner entries for you. While the car keeps rotation off throttle, the center of that rotation seems far more in the center of the car now, than in the back, which makes it rotate more like a mid engine car. The rear doesn't feel quite as exposed on corner entry, and you can actually turn into the direction you want to go, instead of controlling a permanent slide. In Q the weight balance is still very far to the rear, hard to do anything about it. I tamed it as much as I could and again no negative toe needed here for (most of the) lap time. 
Especially in the race it feels very balanced and despite the wear difference and front graining, it remained stable as far as I got into the stint. 

Low rake approach for Imola
Here on Imola the Porsche needs a bit more top speed so I went with less aggressive aero. In fact that turns out quite nicely as it also removes the pitch sensitivity, and gives traction out of the slow speed turns. Overall this makes it very stable, while you might be down a tiny bit on corner entry speed. However, on exits, even the faster corners, you still get the car around easily, despite the lack of rake.

Adjustments

• If too oversteery: Stiffer front spring, stiffer front roll bar, less rake. One click at a time.
• The brake bias is tricky. If it's too far forward the front will suddenly regain grip and the rear snaps. If too far back the rears might lock. Higher ABS here if you cannot handle it, but likely at a time loss. Clean trailing will pay off.
• higher preload can give more turn in stability, but will come with more nervous exits
• lowering front and adding rear camber might further stabilize the car
• lowering the caster also gives more predictability
• Some drivers might like a car with less rake for better drivability. It does not seem to be too problematic to lower the wing in turn for 2-3mm lower rear ride height. and you can just as well go the other direction.

Tire pressures
Aim for 26.4 or more. Lower pressures might feel better in a slow corner, but its harder to hit the right slip. Go for 26.7-26.9 for solid support from the tire without surprises. Here its aimed to have the fronts at lower pressures than the rear to have a bit less response on the front while allowing the rear to build grip slightly quicker.

Lap times
Q fuel: 14L
R: 101L (enough for 1h + formation lap)

Updates
- 1.9.5 updated. ignore the 1:39.9 Q lap - missing a delete option ;)