At the time of the article, perhaps 0.32 drag coefficient was good, but technology (to a small extent), and manufacturers willingness (to a larger extent), has enabled a lot of commercial cars to get a lot lower. For example, the 3rd gen Prius, the Volt, etc are within 0.25 Cd.
Of course, as the article said, it is not just drag coefficient. It is the product of drag coefficient AND frontal area that determines wind resistance. Being a sports car, the NSX has a pretty small frontal area.
I've always liked the Autospeed articles. They are written well so most folks can understand them, and written by people with actual engineering knowledge - not just some "tuner" repeating what they've heard from other "tuners."
Autospeed also posted another aero article where they put small tufts of yarn over an RX7 
FYI, here's a few more snapshots of the NSX in flowstream testing. You can get an idea where the flow separates, the boundary layer thicknesses, and where the flow reattaches. It's obvious the NSX-R wing is more effective after seeing these photos from the regular one.
Dave
