Aurelia, GW doesn't want you to know this, but you CAN put all four sponsons+Lascannon turrets on the Baneblade. (It's actually pretty easy, build the front and rear sponsons as you normally would, then put the second set of sponsons on the rear of the tank, so the bolters (or other weapons) face the rear of the vehicle. The front sponsons just go on normally, at the front.)