I'm making 3D cake in the shape of a car. I have different recipes for the sponge that all vary slightly. Eg. butter cake, sponge cake, pound cake. The ingredients are sometimes exactly the same but the quantities vary, eg. some use more eggs, some use more butter, some use more sugar, some use milk whilst others don't. The cake will be cut into pieces to assemble a car, and it'll be enveloped entirely in a homemade fondant icing. I suppose the cake should be reasonably strong to withstand all this.