Raced German engines akin to those used in WW2 were only raced by the Germans AFAIK before WW2, as part of Mercedes developement process and for governmental propaganda purposes.
Working DB's thesedays are too rare, hence are even more expensive than allied WW2 engines, and also the lack of spares; what spares there are today, are mostly all from expensive limited runs of 'custom made' batches of only a few specifically needed componants.
The T80's aborted DB603 became the step-father of the to be developed DB605 I believe.
Incedently offtopic in a way...
The last WW2 era DB605 I believe that was installed in a 109 - possibly now in Black 6, was found hidden behind a false wall in a Cagiva/Castiglioni factory in Varese or Bologna, Norhtern Italy, in the early 1990's when they were extending the factory;prior too the time when the iconic Ducati 916 was launched.
I read this in the same 'Bike' UK magazine as the test review of Honda's NR750, then the Worlds only 'production' Oval Piston engined vehicle/motorcycle in '91/'92.
The NR750 was/is most expensive 'factory production' bike a over £36,500, of which most of which ended up as Japanese 'Race Marshall' bikes at Honda owned Suzuka the now abbandoned Montegi circuits - each bike was sold at a massive loss, although Honda has/will not state(d) by how much.