Fwiw, I think that in academic studies Toscana is usually separated out from "Central Italy" as being more "northern like" than Umbria, Lazio and Marche, with affinities to Liguria and Emilia Romagna. It's very visible in the yDna as well, with its much higher levels of downstream R1b.
There is also, I think, a cline in Toscana, with the northwestern area, i.e. Massa Carrara, skewing slightly differently. There are not, however, to my knowledge, any samples from those areas in the analyses.
If you were going to be precise about it, Lazio is problematic. Gaeta and Formia in the far southern part of Lazio were never historically part of Lazio (added by Mussolini if I remember my history correctly), and are, in both genetics and linguistics, part of Campania to its south. Latina, or the Pontine area, was part of the province of Rome, but was settled by the Pontine Italians from the northeast, although I don't know how many are left or who else settled there when it was reclaimed. Rieti used to be Abruzzo, right? I don't know about Frosinone. A lot of people from there came to the U.S., and I know more than a few. They strike me as quite different from people from, say, Viterbo. I'd be interested to see if they're closer to them or closer to people like the Abruzzesi or Campanians.
The same thing arises for Trentino. You would have to be very careful to get people with "really" deep roots.
Abruzzo is a mix of "central" and "southern", I think, but quite a bit more southern than central, imo, as makes sense since it was politically always a part of the "southern" Kingdoms of various names.
These things, which I've been saying for years, are all borne out, imo, by the graph put up by Jovialis in post number 86
I think we all recognize these differences, which are part and parcel of the diversity of Italy, and the various clines, both north/south and east/west. It's just a difference of nomenclature in the clustering.
Just a note as to calculator PCAs. Much as I like the old Dienekes runs, they, like many such runs, included samples from individuals who sent in their data. That's true for Eurogenes too, I think. There is no way for these people to check the ancestry of these submissions. At least in academic ones they check that all four or at least 3 of the grandparents are indeed from the claimed areas. Actually, these analyses should only be based on people with much deeper roots, but that's another story.
I also think it's very unwise to try to judge "genetic closeness" by distance on a PCA, which even if perfectly done, with perfectly chosen samples, only covers two dimensions. I think fst is a much better bet, which is why I posted some figures above.