Biggest two things are traction control and tire pressure. It would require seat time in the fixed setup, which is very different than what I would (and will) run in the official series through the week. Tire pressure would have helped mitigate how slippery it was on cold tires because the second session was pretty slick before temps got up.
That's what I mean that for me and a lot of other drivers, the setup isn't about moor speed, but finding something stable according to their driving style and familiarities. I have plenty of seat time but I've been using pretty much the same set in the BMW since week 8. So that's why I was a bit thrown off.