I drove many 6 speed manual and auto equipped late model C4s (94 to 96) and C5s of all years except 97.
Manuals usually feel quicker and more responsive, additionally with automatics there is a performance rear gear ratio and a standard rear gear ratio. The manuals have just one rear end ratio.
The auto equipped cars don’t require any skill, and I clearly beat some faster cars both on the street and at the track with my 95, and they had 6 speeds. ( You cant miss a shift with an auto)
My current 99 has a 6 speed and runs mid 12s when I remember how to come off the line and shift. I love the feeling of a 6 speed stick, until I go to the track.
Some auto equipped cars I drove felt pretty sluggish – but there are so many possible variables.