So I wanted to give an update. This is a sad story, so get some tissues ready.
I did take it in, and both the upper and lower manifold, and the gasket on the lower had to be replaced. The metal had actually been eaten away by the coolant. Came out to $1260.
About a week ago it spun a bearing, and there is a horrible knocking sound, so the engine is pretty much shot. The car is finally dead. I wish it hadn't come so soon after such an expensive repair. Weird thing was, there was no coolant leaking into the engine, no foam in the oil, no oil in the coolant, etc.
If I had some land, I'd put the thing up on blocks and part it out, as there's a rebuilt tranny and new rack on it, both within the last three years. It will end up as a trade-in and I'm sure the dealer will junk it.
You guys have been helpful during the time I've been here, so I did want to thank you.