I'm fully through the book now and there's nothing much to add to Pometablavas comment,
a great compendium, showing that during 1945 the days of the piston engine were far
from over for the deutsche Luftwaffe, a point, that could easily be forgotten,when
looking in other sources about German aircraft projects from that era. As mentioned in
the book, the reasons often were the need for longer range/endurance, hard to achieve
with the fuel thirsty early jet engines. On the other hand, as mentioned for example
in Ralf Schabels “Illusion der Wunderwaffen”, there was still a quite widespread re-
luctance to rely fully on those “new” and still unreliable engines, not only amongst
military staff, but even amongst German designers. BTW, an index of the used sources
was he only part I somehow missed, but nowadays additional information is quickly
available via "the net". And Justo avoided for example the trap of designating those
combinations of the DB614 engine with the MK 214/412 gun, (drawn by Daimler Benz) as
"projects",or even "Fw 190 derivatives" !
Just a snippet, of course, but those who know, what other authors already had made
of them, is glad about the proven research here !