I'm in the same boat is .Cd. Joel's Mazda5 had a CoD of 0.29 and thats a big honking minivan like vehicle. The Insights CoD should be much much lower. Heres a pic of the front end of an Insight. The hood is unlatched.
The stock cooling system uses a half length radiator for the engine, and a full length evaporator for the AC. The batteries are air cooled internally using the cabin air. I haven't really driven mine around, but the cooling system only takes a gallon of coolant for an overhaul, so I am figuring the engines cooling demands are very low. My gut feeling is that its low enough that even a half radiator is overkill. My plans are making a grille block on the top most radiator opening, then depending how well that is working, block off the bottom. The bottom opening is fitted with a grille to deflect air upwards into the engine bay. The front plate bracket I really want to get rid of, but I'd need to find a good way to relocate the plate.
I don't have any pictures of the underbelly, but there appears to be full length panels running underneath covering about 75%. Waiting to get my Dad's Camry fixed up before I can put Rommie on the ramps and get a good look.