Oh man, I just realized that you can go back and see your scores for each level. I didn't know that before...you can "minimize" the challenge bar on the start screen for each level, and your score is among the "characters" at the bottom, in 1st, 2nd, 3rd etc. place (I guess I thought you could only see this right after playing--when you earned the score.) If several people go back and get their stats, and add them here, it should give everyone a good idea on the scores needed for the various star levels...