Actually, I took the pictures because peeps on the Corvette Forum demand it, and the one I uploaded here was shitty.
I've got a peculiar odor that sometimes shows up, smells like coolant. Could be the heater core, but since it still blows consistently hot and doesn't leave a residue anywhere I don't think that's it. My next guess is a head gasket, some gunk flew up onto my windshield from under the hood while driving today and wouldn't wipe off with the wipers.
Best case is that it's just some seepage from the radiator due to a worn cap or hose. I also need to grab myself a new O2 sensor, because one of the four went poof. Car still runs fine as far as I can tell, though. No overheating, funny noises, etc.
Besides, even good condition C4s are cheap to buy. Nothing awe-inspiring about it other than that they are awesome.