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Once the spring mount ring gives up the ghost, they won't work at all. The G-spring wears an indent into the ring where it pings back off the ratchet.
Once the indent is deep enough, the tension of the derailleur spring will overcome the shifter and you will lose your lower gears.
8 speed kit is going to be twenty-odd years old by now: early 9 speed has the C-Record era "look" (you could polish the branding off) without having one foot in the grave...
If you want mid-Nineties Campag, get 9 speed: the spring mount rings are still available, unlike for 8 speed (the G-springs are unchanged between 8 and 9 speed).
And no, the premium Record commands over Chorus isn't worth it.
"carbon" refers to the body of the shifter, so fractionally lighter: '94 Record got it first, then '95 Chorus.
If you must go 8 speed (but don't), then the look for "BB-system" on the body: the mechanism operates on ball bearings rather than bushes.
PS "Brifter": just don't.