Re blossom’s post 806: I disagree with you about what would happen to research grants, if MIT took merely good undergraduates as opposed to excellent undergraduates. That would have essentially no impact. The research grants to MIT depend on the faculty, foremost; secondly on post-docs; and then on grad students. The undergrads do not really matter with regard to research grants, except to the extent that funding agencies like to see an undergrad or two supported on a research grant, because it allows for continuity of the pipeline and encourages the undergrads.
One of my colleagues at Harvard remarked to me that he lost ground with every grad student he took, and he broke even on the post-docs. I don’t think he had any undergrads in his research group.