For a race car, I would be doing a single layer of ~200g carbon either side of a 2mm Rohacell foam core. You will get a bit of print-through, but on a race car I prefer that over extra weight for the sake of cosmetics.

Also a good idea to identify where you are going to place your pins beforehand, then cut the foam core out in those areas and replace it with solid carbon (so for a 2mm core you would need ~8-9 layers of a 200g material). The pins can place quite high compressive loads on the panel which the foam core won't like, so better to have monolithic laminate in those areas. Not as important on a bootlid, but good practice.

I've finally gotten a mold made for my bmw e30 racecar trunk/boot and I am starting to plan out the layers of materials so I can infuse the part.

Are there any general recommendations on how many layers and core material to use? This will be basically just a skin part (I won't be making the inner structure like was done in that mini cooper bonnet video from easy composites) that will be pinned to the car. Obviously the car is only for track use so lightweight is the goal, without being to flimsy.

Thanks for your help!