Get the coolant tank checked for exhaust gases. Many many late 90's legacy models with the 2.5 suffer head gasket failure... speculation says it's a manufacturing issue since the head gasket has undergone about a half dozen revisions since it was introduced.
Also drive a few tight figure 8's in a parking lot to check for binding. If it feels like it's sticking or having trouble in tight turns, I suggest walking away.
AWD Binding and Head Gaskets are the main issue on these cars from my personal experience and observation.