M104 Sombrero Galaxy - now classified as elliptical

[25585]

I was interested to read on Wikipedia that M104, known as the Sombrero Galaxy, has now been re-classified as elliptical (E) rather than as before spiral (S) in Hubble categorisation. 

Before it was classified as S0, a spiral with a small disc, but data on the dust lane (hat rim) is now not considered a spiral galaxy's disc, and M104 is now a supergiant elliptical E1. 

[pipnina]

I wonder why exactly they decided to change its classification. I suppose it doesn't really have "spirals" as much as it has a torus of dust. This is visible in the hubble observations from more than 15 years ago.