Insane, just f***ing insane.
This spring I rented E-class in Dusseldorf, Germany for 3 consecutive days and ended up paying less than EUR 100 for all three days in total (at Europcar) having a rate of less than $50 per day. Not sure if it was a special promo or something like that as I booked it directly on europcar.de, but I routinely rent nice cars in Germany and France for a fraction of price of similar rentals in the US.

Apart from that, what's really the reason of renting any powerful car in the US with countrywide speed limits of 75-80 mph at best? (which is ~130 kmph - only 70-years old folks drive like that on autobahns in Bavaria ). It's a truly great pleasure to drive 200 kmph in a nice Audi on A95 heading to Munich and watching Porsches and other supercharged cars disappearing from you quickly in the left lane, but I don't even want to imagine myself driving 70 mph in such a great piece of German engineering :-) (yes, my speeding tickets from France are already paid - lesson learned).

So my vehicle of choice here in the US is Chevy Aveo :-))) (or Chrysler 200 even better). No chance of speeding ever :-)