Your English better than my writing in Dutch
Correct, bike in the photo I posted have original DR800 swingarm.
Another guy converted his DR to similar bike like you have in your picture. He used GSXR swingarm. I think bike in your photo also have GSXR swingarm. And this swingarm is much worse than DR original. He says it is too flexible.
We with my friends measured Bandit swingarm and found, that because of different levers in progressive system, different axle and a bit different width it is lot of work to adapt it to DR. Then one of guys measured weight of aluminium Bandit swingarm (new model) and it turns out it weights not much different from DR original. So - there is no win in using it
Original SR43 swingarm is very rigid, this is why it is so bulky.
One more photo for you

this is same GSXR swingarm I think.