Looks very impressive mate, well done
Better considder the level of the main mesh tho... judging from that last image you started off with a fairly low poly mesh... And now your at a point where a closeup would be posible, but the main mesh just dosn't have enough polys for it
If you can I'd say go over the mesh again and considder where you want the dense greebles and details and then up the polys there... especially around circular areas like in that last image.
But damn, you're moving fast man