Seeing Leipzig in the top 4 is normal and I am happy that this team does not lose its consistency every season. However, sometimes there are things that will prevent them from maintaining that position and Wolfsburg will indeed be quite a difficult opponent to beat. But in general, Leipzig can handle it and will continue to keep their distance from Dortmund's pursuit. The season is still long and I see it as just normal competition in the Bundesliga and maybe if Leipzig slips up, Dortmund will make good use of this to shift their position from the top 4.
You are right that seeing Leipzig in the top four is a normal thing because for several seasons they have appeared as a team that is consistent enough to occupy the top four until the end of the season. What is surprising is how Stuttgart and Bayern Leverkusen have become new forces this season by making it difficult for Dortmund to be there in the top four and the most surprising thing is how Union Berlin is so bad this season when compared to last season.
Facing Wolfsburg will be an even match, Leipzig just needs to be aware of all possibilities because Wolfsburg certainly doesn't want to lose at home and also Wolfsburg is currently trying to end their bad results in the last few matches because if they don't recover quickly Wolfsburg will further decline in position and of course mentally their players will be increasingly stressed because they have not been able to end the bad results they have obtained.