Grill block would be my first aeromod. Warm up time is enhance as is aero. On a hybrid, the ability to stay warm really helps out too, especially in winter.
The wiki has a decent list of mods and what they've done for people who have done testing. That will give you a rough idea of what kind of benefits you should see.
http://ecomodder.com/wiki/index.php/...fications_Main