I think our district used this curriculum for a time. I assume this is the same one.
A friend of mine told me that his child had CSMP in 2nd grade. Six students in the class went on to take BC calculus in high school, a very high proportion. (A couple of years ago we had 12 students taking BC calculus out of a class of perhaps 150. In other years I believe we've had as many as 20 students in BC.) There were no more than 23 students altogether in the class, which was not tracked.