The 94-96 (manual) had a 165hp or a 180hp injection pump. The later 96-98.5 ( manual) had the 215hp pump. You get better mileage and more power (with add ons) with the 215hp pump. Also the plungers were designed in such a way as to have a better torque curve as you went through the rpm range.
The one you saw on ksl is an automatic, so it would have the lower power hp pump. The auto's always had the lower hp pump.
Compression numbers? That is a question for Muddy. Unless you have the tools, you'll have to take it into a shop anyways to be checked.
With the economy being what it is, there will be more trucks for sale.
Personally, I would look for a quad cab for the extra room.
Have fun looking

. Unlike a boat purchase, the happiest days of owning a Cummins is the day you purchase it, and every day you drive it.

Unlike a boat, where the happiest days are the day you buy it, and the day you sell it.