Mate, this is superb! I didn't know you can do all this with Gran Turismo, and the end result looks fantastic. I remembered back when in NFS Underground, and Most Wanted, when you couldn't even orient the vinyl 😄... Ah, technology. My compliments for including the Vulcan and the F40!
With Gran Turismo Sport you can create almost any design that you like. The key is create your images using your own tools and then upload them to Gran Turismo. The images also need to be in svg format and under 15kb. That seems small but it is not difficult to reduce the size of images. If the image is still too big you could break up the image into separate svg images and combine them on Gran Turismo.