The few R80 bikes I've seen have always been a bit smoother running than the R100 bikes. They offer some more "grunt" than the later model R65 bikes but not as noticeably a difference as the R100. I've look at some R80 bikes lately too, but as I am contemplating adding a sidecar to it at sometime, I think the added power of the R100 would be a definite "plus" for that application. But riding solo, or occasionally 2-up, the R80 is a nice machine. That price seems steep, though I don't know if there is a conversion rate where you're buying it from?
IF not, another will eventually come along, ya just gotta keep looking and be patient, like a hunter!