I only mention Finland because they start schooling fairly late. Without formal 3Rs prior to 7, kids appear to do fine. It seems to me that for example starting math prior to 7 or 8 has a chance to do more harm than good if a child's related metaskills and abstract thinking aren't there yet.

Utramarina, we are in a very similar magnet. The school makes a point of bringing best practices from the magnet side into the regular classroom. There are programs like "reading buddies" where gifted kids volunteer to help with reading in lower classes. The success of the school and the non-magnet students have all improved signficantly over time since the magnet program started a few years ago.