My Grandma has a 3d Corsa C ('00 or '01, iirc), I drove it for years when living with her. It had the 3-cylinder 1.0l engine. Enough for city driving, maybe underpowered if you like to pass Merdies of the Autobahn, but Grandma says she once tested it up to 150 km/h. Since the Corsa C has very wide side mirrors, we always folded them when driving into the garage, and never felt like unfolding the passenger side mirror when going somewhere. Believe me, that car needs a pass side mirror only when hauling big cargo inside. Folding one mirror will reduce frontal area.
I'm with Rob on the grille block and weight reduction. If you can't find an OEM undertray, make your own out of coroplast or aluminum. Rear wheel skirts!!!!!!!!!!!!
Because of the high mounted rear lights a Kammback may be out of the question, unless you use plexi or lexan or whatever.
But driving style makes the biggest difference.
And read lots of EcoModder.com
