funny enough, i think it is only 5% of german autobahns that acctually have no speed restrictions if you take all the construction sites that slow you down into account.
i have to admit though, it is amazing when you are cruising at 140kmh in a BMW 3series and when you floor the pedal you acctually feel a strong response
hitchhiking in germany once i caught a lift in a 911. the guy sticky taped a 50DM bill to the inside of the windscreen and said: "mate, i am going to accelerate now. if you can grab the bill while i do it, it is yours."
what followed was the most awesome display of raw power i have ever witnessed. i didnt manage to grab the bill btw.