All 2.8v6 Signum and non Vxr Vectras are auto only... Exception being the plod ones which were Sri spec with full 280 and a manual box...
The 3.2 versions of both cars were available in manaul and auto form as both Elite and Sri, but non plod or Gsi manuals are rare at best
That statement is not correct at all, there are manual 2.8 V6 Signums about - when I was looking for mine, of the 4 for sale at the time 2 were manual
They never made a GSi Signum, or indeed a 'sporty SRi version', Signum was only available in Elite, Design or Elegance spec iirc, but most GSi Vectras are manual as are the 2ltr turbos
Having owned a 3.2 Signum and now the 2.8, the 2.8 is a far far far better car to drive, actually makes the 3.2 feel pedestrian and gutless (still own a 3.2 Omega and as it weighs the same as the Signum, I can directly compare)