The Ex-S Gundam is by far the most complicated kit I have done to date. It has 580 parts and was the first modified gundam that I finished.
I still don't know why I decided to make my first mods on a kit so hard, but I when I look at it now, I think that it did pay off. I made 193 pla-platings for it and added another 394 Kotobukiya parts. It took me 6 months to make this kit.
I am currently entering this kit for the First Euro Gunpla cup 2011.