FYI, Buick has revealed that they're bringing the Insignia to North America as the 4-cylinder Regal for 2011.
Could this be the (production) Buick with the lowest Cd ever?
source:
2011 Buick Regal returns with four-cylinder only engine lineup — Autoblog
Of course, there's no telling whether the Regal will get the aero tweaks of the most slippery version of the Opel, but at least we know it's
possible.