2 cents from an Enginerd;

     Yes the power required to overcome air drag increases as the cube of
velocity.  However the tables you guys are showing are listed as Total
Drag.  This would be mechanical (rolling,drivetrain) resistance + aero
drag.  At low speeds - <35 mph (approximation) the rolling resistance is
higher than aerodynamic drag.  To take this total drag figure and
extrapolate it to 112mph is probably not even close to accurate.  I don't
know how fast rolling resistance increases with speed, but I know it is
only a small fraction of total drag at higher speeds.
     I have not had my SVX vanagon over 85 and I might never do it.
However it is accelerating pretty darn fast at 85.  That means I have a
huge amount of excess power available at 85.
     I would say my van is accerating at least as fast at 85 as a 2.1 WBX
is acclerating in 1st gear with your foot on the floor, maybe faster.

John
87 Westy SVX