Ahh if it was a manual, I'd say sell it to me.
As far as your speedo cable goes, I recommend getting a new one. I had the little plastic piece on mine snap off and putting in a new one is fairly easy. They are $40 from Nissan, so probably very cheap from a junkyard.
not sure about the rest of that stuff.
I've seen sentras with minor problems going for around 800 these days.
I say put in a motor from an se-r and profit.
91 se-r's