I've got bikes all up the STI line from Tiagra to Dura Ace, assuming the brifters are not worn out, with the cables in good shape and properly adjusted, they all shift like a dream. Being primarily a crit racer, I ride a bike in those events with Tiagra brifters because I really don't like getting crashed out one of my full DA bikes. The body will heal, but busted up bike parts go in the trash.