@Tomba: the pit entrance seems to be at the end of the horribly narrow chicane you mention, in the last photo posted. It is in the same position it is today.
I do not like the architecture of the pits: I find hard to understand the purpose of those white cones on the roof, identical to the ones that exist in the back stretch... are they the same?
However, I like the "second floor" parking for trucks, visible on the second photo. Maybe they could allow you to park your F-1 car in front of the podium.
Are there such high drops at the side of the track as the ones shown in the model? I know Spa is in a valley, but it seems an extremely dangerous drop (or a mistake in the model).
The last curve (the right hander part) on the chicane mentioned by Tomba seems to be four or five meters above the level of the two white roof "houses" or structures, on the foreground to the right. It seems that if a car goes off the track it will land on the roofs! The same drop seems to exist on the straight before the chicane. This could be a mistake of the model or simply an exageration of the topography. Look at the same curve (from the opposite direction) today:
Finally, if you google for "Spa racetrack renovations", you find the Wikipedia article on Spa. The link given in the Wikipedia article to find information on the renovations, points to an article in this forum.