One important example is missing:
Ford Scorpio I (worse than the Granada)
Scorpio II (worse than all)

- Mercedes W210 (worse, much more unrelieable than the W 124)
- W124 (same situation 11 years before, compared with the W123)

- all Benzes after 1991, as the fans are saying. Some say after 1993

- all Opels from the Lopez-times, at least all from the times, when US-americans were the management

- all VW's from the Lopez-times

- VW T4

About Ford: in a classic magazine was written once, that the best and most reliable fords had been in the T- and the A-Model, the V8, too. In Germany the 1939/41, resp.1948 "Buckeltaunus", too - but everything following was worst. The first trace of reliability came back again with the first Focus (resp.the design ist terrible disgusting).

About the Signum: it's nothing else than a Vectra C with a cutted back. The whole car up to the C-pillar is identical.
And the Omega has indeed much more space than them. The Opel-salesman has confirmed that, when I made a test-seating some weeks ago. He told me, that some customers, which still have Omegas, want to keep them longer, becaue the modern Opels are so narrow inside.
This is true, as my own experience of the last week has confirmed