Well since no one answered the call, I gave it a shot, and after fumbling around for a while, I managed to fix it myself. Thanks to @RMi_wood for throwing me a bone. As I said beforehand, this track has been the unfixable one for me and others for quite a while. But I finally got it off my plate.
AI plus Rain FX for Fiorano 2017 by patrikpat (Speed and Test layouts):
Tested most Kunos Ferrari's, Kunos GT3's, and RSS open wheelers at 100% strength and aggression. Unfortunately, the Kunos Ferrari F1's ai kind of sucks, tbh, so they don't work nearly as well as the RSS cars. I've noticed this while working on other tracks as well.
While I was at it, I also did a rain fx config for the track.
Pit Lane fix plus Rain FX for Autodrom Most by TMM:
A member at RD asked me to look at the track to see what was up with pit lane. Fixed it, and added a rain fx config, because I like to torture myself.
Over and out, hope you all have a great day.