German here. No normal untrained person should be driving at those speeds. The general recommended speed for the autobahn is 130 km/h. Typical speeds on the middle and left lanes are up to 200 km/h though most days the typical "high" speed is probably closer to 170 or 180.
With good weather, no traffic and no roadworks (hah) you might be able to go over 200 km/h for a while but unless it's a long straight stretch you're probably way out of your comfort zone unless you're an experienced driver.
I would say a normal untrained person is safe to drive at speeds up to about 180 km/h. Most ordinary cars seem to handle noticeably worse with every 10 you go beyond 160 km/h or so.
And of course the entire discussion of typical speeds is philosphical when most of the Autobahn has speed limits (roadworks often limit the speed to 60 or even 40 km/h (or less) and even on normal parts the speed limit frequently is as low as 120, 100 or 80 km/h).