How about tires/width and bodykit? I know the different splitters/spoilers can have a 10+/- impact to PP.
Also, regarding liveries…while most are available, I was pleasantly surprised to find the livery maker easy to wield, if only a bit tedious. The real heroes are the folks uploading all the decals - I have made three or four (IMSA) liveries where I was able to pull up a picture of the car on my phone and haven’t yet run into missing decals/sponsors/etc. when going at it. Good luck!