A couple ideas.
You can google "civic hybrid battery" and "Civic hybrid add battery" and see what comes up. I found quite a few pages on problems with the battery but that might just be a small percentage of "squeaky wheel" owners; I don't know.
Also see the em garage page here:
EcoModder Fleet list - EcoModder.com. Use the search tool there to find the Civic Hybrids and see how people have done with them. You can click the cars' links to find out if they've been modded, etc. Click the car's mpg to see their gas logs.