Check the rear ends of the sills carefully, particularly around the jacking points on that 960 - also check how it sits when you first arrive, should be level. If the back end sags, when you take it for a test drive, do about half a mile (not much more thogh) and stop somewhere level and check it again, should be level by now - if not it likely needs new Nivos on the back. They are expensive and difficult to find.
Also the engine should be very smooth and quiet, if you can hear any slight tapping from the top end and a hint of a misfire with it, some Carlube ATF-U or NAPA MVA ATF added to the engine oil will almost certainly fix it - will improve the hydraulic tappets and piston rings in any case and help revive dodgy oil seals in the engine. About 0.5L normally does the job.
The 960 is better appointed than the 940 but 940s are more plentiful. On a long journey, the 960 should be no less economical than a 940, possibly even better. On short runs (most days a couple of 1 mile ish runs) i get 24-26mpg from my 760 (with a V6 instead of a straight 6) and havae seen 42mpg on a run with ~30mpg on most mid range motorway stuff.
No reason to suspect the 960 would be much different - it's a bigger engine so has the torque there without the need for the turbo to spool up although if memory serves, once the turbo on the redblock is up and running, it produces similar torque to the 6-pots. That means it doesn't need to be urged to get the torque resulting in slightly better economy IMHO.
Bottom line is it's your choice at the end of it all, unless you're really sure about the first one you see then view a few first. Sods law dictates there will always be a better sounding/looking one come along for sale just after you've bought your choice but that's just life - ignore it and make the best of the one you buy!
