Have fun with your new horse!
Horse names in German are the horse names forever, they do not change. In fact when I first started going to Germany, it was nice that the one thing I could talk about with old breeders I would visit who didn’t speak English was the bloodlines of horses they would show me! The Germans are very strict on the fact that if a horse has been bred, their names can not be changed. It is also rare to change a horse’s name after they have entered competition (except to add a sponsor before or after). Of course, once a horse is imported to the US, who knows, but as far as I know, neither Gardekurrasier or Wendland II were exported.
Gardekurrasier, born 1975, was sired by Gotthard. Wendland II was by Wendekreis. Both from famous old Hanoverian lines. Gotthard’s were great jumpers but some think they are difficult. Wendekreis produced solid horses (in mind and body)
In German addresses, the house number comes after the name of the street, and the postal code comes before the city. So a US address that is
123 Main Street
Anytown 45678
would be written in Germany as
Main Street 123
45678 Anytown
Therefore, Klostertaler Str. (abbreviation for Strasse = Street) is the street name and what you think is a G should be a number (6?). Or perhaps its a very small street in a small town so there is no house number. That would make the most sense because if the G is a 6, then 66757 could be the postal code, since they are 5 digits. and Braz would be a town.
As far as the “D” line being good jumpers, Dynamo is not a typical representative of what we see as the D line today, via Donnerhall. Some of them can jump, but a big scopy jump it isn’t what you think of with them.