I have 2 friends in that school district. They do "in room" differentiation until 3rd grade which is highly teacher dependent. They have pullouts for LA and Math from 3rd onwards. Apparently, they use the STAR test scores to select the top students and then administer a COGAT type test for the 3rd grade pullout selection - I am not sure what the cutoff percentile is. My friends think that the differentiation is nothing special and have their kids in after school academic enrichment as well as in summer camps. good luck.
