Westwinds are great airplanes. I really enjoyed flying them, both the I and the II. The I flies a little bit nicer, and will do most everything the II will do (but goes a few knots slower).
There are lots of gotchas with them at this point. That one doesn't appear to have ADS-B, which is a big red flag-- not so much because it's expensive to add (it shouldn't be too bad), but rather because it indicates it probably hasn't been flying recently. And if it hasn't been flying recently, there is a decent chance that Honeywell will insist that you overhaul the motors. I believe they have a requirement to be run every 30 days, and they are pretty strict about that.
And, unlike the 331, the 731 doesn't have "overhauls" but rather "major periodic inspections" (MPI) which means that you can't run it past the overhaul time, since it's a required inspection.
I wonder what on earth happened to this poor thing?
https://www.controller.com/listing/for-sale/203508523/1981-westwind-1124a-jet-aircraft