I did one a number of years ago. i used AudioNote Copper caps and a TKD volume pot. those changes made the preamp much more detailed and so much more musical.
The TKD volume pot was a surprising upgrade. the copper caps made the whole system sound bigger more open and much more musical. I bet the Evo's will be great in this spot as well.
I recommend you change out the volume pot as well while your in there. I don't think Cary used overly great ones back then. The TKD's as well as others i'm sure will be a surprisingly good upgrade for not a huge cost.