As far as I'm aware, yes. JSI is the only upgrade system I've heard of for the CD-80.
As a side note to those with CD-80 racks older than the SV, the JSI upgrade allows you to use JSI non-dimrelay modules, whereas there are modules available for the regular SV that will do on / off relay control.
I bought a Strand C21 conversion chassis for a CD80SV, on ebay. I mistook it for the version that fits the CD80AE rack I have, so I can't use it. I don't know if it works, but it looks fine. I'm entertaining offers for it.