There's a suspicion between us drivers that the physics had been changed on the build we were racing with at the Nurburgring, so the following comparison might not be 100% correct, but...
There is much less grip with a wet track surface.
People were suggesting the reduced grip could be purely down to the heavy wet tyres we were using, but I've just got home and compared my times with the same settings on a dry track.
Subaru Impreza, 99% power, 100% weight, brake bias 1 and torque distribution 40:60 which is what I opted to run during the Repechage race.
We were running 1:44s in the wet and I have just ran a couple of 1:37s, so much quicker.
The closest you will get to replicate the conditions we ran in is with comfort medium tyres. However, it's not that simple.
In the rain, there is more power understeer and more power oversteer. When the car begins to lose grip (front or rear end), it is more pronounced in the rain. It is also easier to turn the car using the brakes in the rain, which I found crucial to tackling the downhill turn 3.
Nothing can set up you for how slippery the kerbs are. They will try and kill you. Even with a 40:60 torque distribution, the rear comes round on the inside kerb of the first right hander in sector 3. You won't believe how tricky the braking zone for the last corner is on the exit kerbing of the previous corner.
Another thing to note is the wear. PD didn't tell us the multiplier they applied for the wet race, but just now in the dry with a multiplier of x2, my tyres wore quite a bit faster than in the wet. Which is expected.