I realize I'm late on the conversation, but I too would have to say an engine bay should match the body. My poor car was victimized by some stupid teenager before i got it. Rattlecanned black right over the factory teal without ever removing a damn thing.
I haven't had the time to pull the engine, clean out the bay, sand blast it and fix it all up. That is going to be my next car. Its taken me damn near three fucking years to get this one finished...
Speaking of paint...
I tried spraying a pearl basecoat outside. I found, to my great displeasure, that you cannot sand a pearl without painting it again as you will damage the flake causing irreversible scuffing. You can, of course, paint it again, but make damn sure you have your gun and your air set up exactly the same way, or your pearl will take on a different grain from the rest.
I live in Maine, the thought of being able to paint at 92 degrees makes me giddy. I couldnt even use medium reducer last summer until the middle of July, and two weeks later it was back in the mid 60's...