300 km/h (186 miles/h) is surely a bit too much, even on a "Autobahn"... but just coming home from over 1000km across those Autobahn this weekend, i have to say that driving there with 120-140 km/h (80 miles/h) was a *lot* more stressy and unpredictable (mostly the 2 lanes at right side if 3-lane-highway) as driving around 180-200 km/h (118 miles/h) at the 2 lanes at the left. Really!
It maybe has something to do if the drivers are concentrated on driving or on the spring around them...
When I cruise around 120 km/h, I sometimes catch myself getting unconcentrated on the trafiic around after a while... Don't get me wrong - I enjoy cruising, but after that trip today, I'm unsure at which speed I feel safer....
Okay - i must admit that it's around 180-200 km/h *whistle*