Do make a 3D outline you simply extrude out edges along the ‘seams’ of your reference images. (the places where the metal plates come together.) And of course, you’ll need to constantly work back and forth between your front and side refs to make sure every edge gets in the right place. Once you have this outline, the next step (in my approach) is to fill in the empty spaces and make a solid model. (no ‘seams’) This lets you focus on getting your topology clean and smooth (that was my biggest problem in my other car modelling approach). After you have a clean solid model, use the V command (rip tool) to separate the individual panels.
Thanks for the question, and peace out :RocknRoll: