The rear of the ship with the appendages is really good - the main body of the ship is a little too much like a blimp (and ribbed for extra pleasure!)
Perhaps if the shape were flattened somewhat? More like the current Nomad Cruiser.
Either that - or split the main body laterally, lose the lower half and have the Sunbuster Gun slung under the fuselage like an 'appendage within the appendage'. The gun joins onto the ship near the back of the main body where the forward appendages come out.
My reasoning is that there would be a gravometric plexus at that point - where the graviton fields for both jump-drives and the Sunbuster Gun would be generated...And it looks meaner;)