The top pic is the original build. The bottom pic is my modded set. The main difference is in the top back section between the "wings". I also rebuilt the back of the cockpit.
Close up of the cockpit. I completely rebuilt the back end which previously sloped down right behind the pilot. Now, it continues back a bit with windows on the sides and back. The turret is now attached to the roof, but can still rotate. The other thing that I changed is the canopy. I actually repainted that with a solid white top and extra bars on the sides. Similar to what Lego did for the Ultimate Collector Series version, but for some reason, they didn't use that version of the canopy on the smaller sets.
Oh, and I replaced the R2 unit with an R5 unit.
Original build on the top, my modded custom on the bottom.
Here is the back side of the cockpit. Original build on the top, my modded custom on the bottom.
Here's a close up of the back detail. This section was completely rebuilt from scratch.
Photoshopped action scene!