I think many colleges will be very receptive to kids who appear to have a lot of potential but come from poorer performing schools. If two kids have the same test scores and one came from a high performing school and the other came from a low performing school. They will assume that the one from teh low performing school has MORE potential; it just hasn't been tapped yet. Schools like to have a well rounded demographic and don't want to just be filled with kids from prep-schools etc.