My car history is way too long to list, but the XMs in the OP's post lead me to mention that I was a major Citroen CX fanatic back in the day - I owned 5 of 'em in succession - the last being a GTi. Lovely old things they were - incredibly comfortable and quite entertaining to drive as well.
Highlights from the rest include an early Aston DBS (back when they could be had for fairly sensible money - running it was another matter, however
), a BMW M635csi, a couple of Datsun/Nissan Z sportscars (280zx targa and a 300 twin turbo), several Saabs (another long-term obsession of mine - first being a 96v4, the last a 9-5) and a Lexus GS. The Saab 9-5 and the GS were what filled the gap between my first A8 and my current one.
The CXs and the Lexus were the only things that came close to being as comfortable as an 8.