You can put shading on parts, however keep them consistent with the shading on the rest. right now, there is more shading on the egg then on the hovercraft
that said, I think the frame under the egg would look better with a 3 line frame instead of a 1 line, but try it out for yourself. The skirt is relatively soft, so use rounded lines, no hard corners. Choose a colour scheme for everything (parts, hovercraft, whatever) and stick to it. and I am not certain the WM is on the position it should be right now: the radar in the bottom half looks to be mostly blocked by the surface search radar on the pilothouse and the propulsion, should it not be slightly higher?