Bostonianish person here: it hasn't changed Boston. My brother-in-law was running the Marathon that day, he finished about 30 minutes before the explosions.
Watertown residents' cars are no longer universally decorated with "W Strong" stickers. The feds had to strain mightily at the jury pool to get jurors willing to consider the death penalty -- sentiment in Massachusetts was 2:1 in favor of having Tsarnaev rot in prison.
Insofar as the Tsarnaevs had a political goal, I don't think they achieved it.
