I think the performance of Suttgart was perfect so far in this season but the fact about this team is mostly about the players they have, I think one good reason for Stuttgart to have this good performance during this season to get the good results was mostly Serhou Guirassy and in the games they didn't have this player Stuttgart couldn't have good performance in Bundesliga.
However, I don't think if Stuttgart can ever win the Bundesliga title considering the performance we see from Leverkusen and Bayern Munich.
They are like Girona in La Liga. Make a surprise with the results of the match until week 16. After 2 seasons of being in the relegation zone and always happy this year they made a surprise. In fact, they were able to put one of the names on the list of top scorers.
Actually, there is still half a season of games, it is too early to guess they are difficult to enter the list of championship candidates. But indeed the state of the player's statistics does not make it certain that they can compete with Bayern Munich and Leverkusen.