Forza livery editor has 1000 (yes, ONE-THOUSAND) layers each side and the hood-roof-trunk part, 500 for each bumper, and 100 for the spoiler. You can select groups of layers, save and load them, copy-paste, choose size, rotation, opacity...
The basic shapes are the same its just MC:LA only allows you to have 100 layers on each panel, Whereas Forza lets you have 1000 on all but the bumpers and the wing which are 500 for the bumpers and 100 for the wing.