Myself wouldnt get anything less than a 2.5 but I know nothing about your budget.
Service History is most important .
Cooling system contains many parts made of plastic which after 10 + years of service go brittle and are prone to failure. Expensive
Auto gearboxes can give trouble as oil is never changed. Expensive
Suspension components front and rear again at this stage 10 + years will be showing there age. Parts are expensive.
Interior dash buttons are delicate and often damaged.
Rust is a big one too now. Around sills. Watch out for rust under mudflaps. Around rear wheel arches and the back boot loves to rust around keyhole and along its bottom edge.

A service history/ receipts for work carried out can help allay your worries as regards a lot of this might have been looked after along the way.
Would try to find one with as high a spec as possible.

Im sure people will add more.