@analogphotog if replacing, its best to verify what uF and voltage caps you have installed now, and if it's helpful to know if they are stock caps or not. If its a used SLI-80, people change them. People sometimes go 1000v when less is not available. May not be necessary, check the caps you have inside now, first.
Having owned the Cary SLI-80 Signature and the Cary SLP-98L tube preamplifiers, and comparing with friends, I've concluded one thing. Changing caps may not always be an improvement, it can offer a "different" sound. It helps to know what you are trying to change to gain more or less of in the sound, if that makes sense.