Just for interest, does Racing the Sun include the Neubauer "Mercedes paint scraping" story which has been proven to be a myth although it is still used by daimler-Benz publicists.
No it doesn't mention the paint story. He doesn't really follow Neubauer that much at all. Also, he doesn't attribute the whole Varzi morphine addiction thing to Ilse Pietsch: the book refers to Varzi developing his addiction during his first season at Auto Union when he was taking medication for his appendicitis. He probably got this from "Una curva cieca. Vita di Achille Varzi", which I picked up myself a few years back, and in which this is also mentioned, if I recall rightly, that Fangio came to Galliate after Varzi's death. (http://www.amazon.it...&qid=1404385267). Apologies for referring to the historical fiction for this, but tbh I was really more just recommending a book to read that making any statement of fact, I recommend reading Una Curva Ciela too.
Anyway, he doesn't mention the Neubauer paint story, and most of Sandro Martini's sources seem to be in Italian anyway (there is a bibliography on his website). As mentioned, the afterword explains how the book was written in terms of research and explains how he tracked down Ilse's actual death date (which varies quite a lot from what Paul Pietsch told Teruzzi in Curva Cieca btw, by 6 years!).
As I say, it's a good read, well I thought so. Having read quite a lot about this era of racing I find mixed reports here there and everywhere on many things, I can't tell you 100% what is or isn't true as I wasn't there, and I wouldn't try to.