As a former B5 S4 owner myself, here's my opinion:
-Since this car listed has the K04 upgraded turbos, that's a plus not only for performance, but in reliability (for turbos). It is important to make sure, the previous owner replaced all things that need to go along with the K04's.
-Imola yellow (I believe that was the name) is a controversial color, but the price seems decent.
-The car is definitely a beast, but you rarely see them on the roads anymore... for a reason.
-There was a popular saying related to this Audi: "Audi's are like strippers, you have to throw many at em to keep em working"