a) for track workouts (mainly threshold work and some speed) ranging from 5:00-6:30, what shoe is better?
b) i tried on the vaporflys, and really liked the energy return/bounciness - does the endorphin pro have this as well?
c) regarding the vaporfly 2 vs 3 and the endorphin pro 2 vs 3 vs 4, are the differences worth the large difference in price? i don't care about colorways
thanks!