Dont really dig the cannon on geom0, the barrel seems like it has triangular shape with only chamfered edges (?), The muzzle could be chamfered a bit better (edges are not eqaully long now). Muzzle could be properly welded into the barrel, too.
Maybe you could put some loose wheels around the wreck model? Might look good
![Smile :)](./images/smilies/icon_e_smile.gif)