Only a couple of suggestions:
1) The wire handles on the rectangular engine plate should not sit up like that. When not being used, they would slide down into the holes. See here http://www.toadmanstankpictures.com/m4e9composite_29.jpg
2) Also your square weld bead around the pistol port: that line was not a weld bead but a seam in the casting mold. The pistol port was integral with the turret casting and not welded in separately. Maybe smooth yours out to almost nothing, I would suggest.