hi shan,
although i wasn't aware that umkc ONLY accepts people into its 6 year program, i'm actually fairly familiar with the school. pm if you need more info.
it's a public school, but they charge in-state students just as much as out-of-staters. they accept both in- and out-staters. as far as i could tell, you don't get much of an actual undergrad education. like any other medical school, if you fail a class, you're basically set back an entire year. this leads to a fair number of 6-year-program students actually spending 7 or more years there. like others have said, umkc puts out mostly primary care physicians. i do know of a handful of people who have gone on to more research-intensive (read: "prestigious") residencies, but this is not the majority.