Hi Glenn,
nice link....makes me miss it terribly :-) There are unfortunately now many parts of the Autobahn were limits are posted due to traffic congestion easement and other reasons. But a lot of it is still wide open...as fast as you and your car can handle.
What I like is the use of displays instead of "fixed" signs. So sometimes the limit may be 100km/h, sometimes 130km/h or the favorite of all a white circle with 4 diagonal lines through it......WIDE Open
AJ makes a good point on the insurance and lawsuit part of it. That is one major difference between here and back in Germany.
Also all vehicles in Germany must undergo a very strict inspection every 2 years..the first one after 3 years...that checks everything for function to 90% as good as new....and if you don't pass...you don't drive until fixed.
Sometimes a fix is technically possible but not approved by the manufacturer and if your car has that particular problem....it's done.
The front suspension on the VW Bug was such an item.....VW had just released the Golf and it was not selling too good..because you know the Bug ...it runs and runs and runs.... So VW did not approve a replacement suspension brace to be welded in.........for a period of years. And then once the Golf was established and plenty Bugs gone to the junkyard...the same piece was suddenly legal to be installed on the remaining Bugs.
But in modern cars....the challenge is really not what it used to be....Our babys for example don't require any special skills to do 140-150 on a nicely paved an engineered piece of Highway....dealing with other traffic is a different subject. Plenty non-german visitors learn that quickly...some the hard way. To counter that the first 10-20 Kilometers inland from the borders are "foreigner-prooved" with speed limits so they can get used to it and mix in a little ;-)
As far as I know you can drive into Switzerland without paying for the Vignette...you just can't use their Highways...but I could be mistaken there ;-)