I don't think they overachieved they just match up well playing small ball vs the Warriors, the weird thing is they may have been exploited if they were to go up against a bigger team like the Spurs...
But as long as the Warriors are the team to beat in the West, it may be best in their interest being one of the few teams that could at least match up vs the Warriors..
They overachieved as a team. They had no business in the post season. Not losing whole starting lineup but their GM had a good summer.