I noticed on the side intakes, side skirts/lower body, front splitter and the rear wing, you colored them black, but it should be exposed carbon. To do this, you can paint those parts on the alpha channel 0,0,0 (black) and save as aRGB DXT5 and that should make those areas show through as carbon.
Just to confirm, I did some research and found a photo that shows these areas as exposed carbon. Click on the pic to see in full size:
Also, if you look in the number 72 car that came with the car, there's an emissive numberplate in that folder which you can modify to make the number plates on your cars light up in game (they won't light up in the showroom).
I believe the ones you want to use are "Numberplate_am.dds" and "Numberplate_am_emissive.dds" and "numberplate_am_nm.dds". Then just copy and paste one of the ext_config.ini files from one of the other skins and modify it to light up the numberplates.
Also, the 51 car should have green window LEDs and the 71 should have blue/purple (probably blue) window LEDs. Page 6 of the PDF that came with the car shows how to do that using that same ext_config.ini file. Basically you hide the LEDs you don't want to use, and then add emissive light to the ones you do want to use.
There's also info in there about how to make the antennas to appear by adding a named texture to the skin folder. Those antenna skins are in the "Antennas" folder in the root car folder. You can see all 9 of these in the showroom. So just add them all and then delete the ones you don't want.
Hope this helps! Otherwise, the skin looks amazing.
Some research for you:
Like this:
