"Germany has no speed limit" is indeed a bit of a myth.

It is correct that, unless otherwise indicated, you can drive at any speed you like on the Autobahn, and you cannot be prosecuted for simply driving too fast.

However, there is a recommended maximum speed of 130 kph.

If you are driving at more than 130 kph, and you have an accident, then the burden of proof is on you to prove that speed was NOT a contributory factor. If you can't prove this then your insurance will only cover 75% of any claim that arises from an accident, so you could be left seriously out of pocket.