The S4 is one of "America's Hardest-To-Get Cars"
http://autos.yahoo.com/articles/auto...t-to-get-cars/
One particular excerpt regarding the reasons for limited supply is worth quoting:
"One official at a German automaker said he keeps supply lines tight so that dealers don't discount the cars, thereby upholding residual values, and promoting brand and luxury value to the dealer and to customers. (It basically ensures that his cars are in "only the right driveways," he said.)"
There's obviously different kinds of reasons that will put a car on this list, though, as the Audi S6 and Dodge Charger wouldn't seem to be cars that are in really high demand.




