A few thoughts from a current DO EM applicant (for the OP and others):
You can do anything from anywhere, and the school's effect on your ability to match in a particular specialty is minimal. This should take a back seat when considering your med school options. Also remember that yes, even your specialty choice may change. I was dead-set on FM, and here I am, absolutely in love with EM.
One big question I will point out: geography. Are there EM residency programs near the school? Will it be easy for you to get there for auditions/interviews? If you're interested in MD programs this is less of an issue, but there are only
50 AOA EM programs, and they're clustered in Michigan, Ohio and the Tri-State area. This can be advantageous in terms of meeting alumni/faculty during your preclinical years, networking, familiarity with the hospitals, and generally making fourth year less of a headache. (I can't speak to MSU from my own experience, but I'll trust Trogghunter and add that it's one of the top DO schools, period.)
As mentioned, a school that lets you do an EM rotation before fourth year is a big help. Many will not let a new clinical student do so, though they may be more open-minded toward the end of third year when you're a little more seasoned.
As mentioned, the dirty secret of pass-fail is that they still know your raw percentage score in each class, and it all goes into your class rank. P/F is a nice 'selling point' for prospective students, but don't be fooled- your class rank will still be calculated and shared with programs.
As for the factors involved in getting into residency, I'd suggest starting with the
2012 NRMP Program Director's Survey, which talks about the factors that determine a) interviews and b) rankings. This is data MD match only, though it includes their opinions on Osteopathic applicants. You can probably extrapolate the general idea to AOA programs. Check the overall data, but the EM-specific stuff starts on page 37. On the DO side, there is the
2011 DO GME Match Report, which uses data pulled directly from ERAS rather than PD opinion to determine what qualities each successful applicant possessed (admittedly descriptive rather than predictive). Again, all good info, but the EM-specific section is on page 27.
More to the OP's point, you can look at data from the 2013 DO match by specialty and then by school (though unfortunately not by combination of the two)
here. Might give you some insight.
Bottom line is that you'll do fine regardless of where you wind up. Work your ass off, do a lot of rotations in EM, and have good people skills. That'll take you a long way.