I bought one of his books in March in advance of a trip to Stelvio in mid may. The book is a great coffee table book, but also has much historic info on the various passes.
In May, myself and 5 friends left our own porsches at home, flew to Stuttgart, rented 2 911 GTS Cabrios and a 718 Boxster GTS and drove 1400km around the Alps in 3 days. Unfortunately mAny of the passes were closed at the top, but it was still a fantastic trip.