I have no doubts about your correct reproduction of the text. But the puzzle car is very different to all other Taglianis known from historical pictures. As already mentioned, the car could have been modified over time, perhaps due to accidents. May be for reasons of simplicity, the upper body part of a BWA was used because no other part was available. I don't know..
Attached pictures 1-4: Two historical Tagliani 500 images, and two 500s from 2007 and 2009
Attached pictures 5 and 6: Historic Tagliani 850 image and Tagliani 850 image 2009
Appendix 7: The puzzle car
Only to clarify: I'm not fighting for points here, but for the correctness of a vehicle description. And I'm not making any claims, I'm just questioning something that doesn't seem clear.