Well, well, well! Was I in for a little surprise!
As I told earlier on, this kit was an inheratige from a deceased friend Klaus, who had begun minor constructing things like putting the engine block together.
Now, when I was trying to locate parts 2-17 and 2-18 (see building plan) I could find them nowhere! I have no idea what Klaus has done with them, but they are NOT in the box!
So I decided to make them myself. I took an old credit card, put it in very hot water and bended it to give it the curved shape of the wheel arches. Then I cut it to the right size.
Next, I took a plastic hollow tube and cut it in half to form the shape that slides over the horizontal support of the car. I glued some plastic sheet to both ends of it, and cut the whole to the right size again.
I glued the curved part and the flat part together, and then the hardest part was to be done : the fitting of the whole to the existing model. I had to adjust quite some things, but finally I got it right to my great relief. Would indeed be stupid to come this far and then give up on a project because some important parts are missing! Maybe I wouldn't have had the courage to do it if I hadn't put pictures and comments on this forum in the first place, so that is an extra motivation!
I finished by cutting and glueing the vertical parts to the whole, and sanding it smoothly. I wonder how I would have done this without super-glue...
Here is how mt Porsche looks like right now, I will certainly keep you informed about the progress of my project!