Frank,
I replaced a perfectly good wire rope for the MP because the extra safety was worth the few hundred bucks. I'd go with the new rope and try to get some bucks back out of your old one. Fortunately, I haven't witnessed any accidents with wire rope on a winch, but some coworkers have told me of some nasty accidents in the logging industry. Apparently, when one of their long cables lets go, you only have a split second to get down or risk decapitation.
As for the chafe guard, I got one from MP along with the line.
Jeff