With the tips I read here, I started to detail the engine compartment and engine lid. I made some mesh for the inside of the air intake and cut some squares that will be the start of the fan housings.
Then I drilled small holes for the bolts of the different panels. I also added a small piece of styreen to fill the gap of the rear lights.
The airfilter also got some minor details. I'd already made an opening into the airfilter, but yesterday I inserted two small pieces of scrap PE to make the two vertical 'struts' in the air intake.
Indeed... I'm doing the small bits these days. Next were the shock adsorbers. The coil springs were caste together with the whole shock assembly. I cut off the coil springs and made new ones using iron wire.

The picture, unfortunately, doesn't show the impovement quite good because everything is black. But thrust me, the new shocks (below) are much better. Then I saw a flaw in the kit. The front shocks should each have 2 coil springs and not one. So those will be addressed too.
Next up where the small squares on the side skirts, which I 'made' using a panel scriber.
While I was scribing the small panels, I noticed that the filler cap for the fuel was sitting on the wrong side. Or was it???
After looking through dozens of photos, I came to the conclusion, that the 959 has 2 filler caps. One on each side.
So I scribed a second filler cap on the body.