I ran a 2.0 auto for nearly 4 years, it was a good car, but was a bit sluggish, but then it wasn't bad.
I have driven a few cars so
Carlton 1.8i auto (DEF)
Carlton 2.0 auto (high compression) (DEF)
Omega 2.0 auto (prefacelifts)
Senator 2.5 auto (F)
1.8i slowest by a long way
Omega a little slower off the line but at road speeds is quicker.
The 2.5 auto Senator - slower than the Carlton 2.0s!! The
boat anchor engine is too heavy and not revvy.
My current 2.6V6 is
similar in performance to the 12v 3l straight sixes.
GUAG list of big Vauxhall autos I have driven
[C]arlton
enator,
1.8 C
1.8i C
2.5 S (a slug which should never have lefted Russelheim)
2.0 O
2.0 C
2.6 O \ Pretty similar, torque & heavy engine vs lighter engine, and a bit revvier
3.0 (12) S /
3.0 O
Not driven 2.6 or 3.0 24V, nor 3.2V6
So my advice is buy by condition, I'd guess that the 2.2 and 2.5 would drop between the 2.0 Carlton and the next pair - 2.6V6 seems noticably torquier than 2.5V6