What are the costs of E50 and regular gas in Germany? I am very curious.

Ethanol in the U.S. can cost 10% or 50% less, depending on what part of the nation you live in.

If ethanol is a much lower cost for you, put in 50% of your tank with regular gas, then top off with E50. The result would be E25 which should work fine.

Good luck.
-John