I'm sure there are many little technical foibles that you can look for but the main things I looked out for when I bought mine last Summer were:
- Usual knocks, dents and signs of crash damage
- Check front splitter - its very low and prone to damage
- Even, smooth power delivery from engine - no flat spots or lumpy power delivery
- Service History (if it ain't full then walk away)
- Has timing belt & water pump been changed at 4yrs/60k?
- Check for grumbles/knocks when steering - this could be faults with diff
- Has it been modified? If so, are they proper ones or Halfrauds Ripspeed Chav cr4p?
- Smoke from exhaust
- How does engine sound when driving? Is noise from turbo consistent or does it fluctuate? - could be boost leak issues if so.
- Has it been on trackdays?
- Check how clutch engages - any slip?
- Is the spare wheel okay and is all of toolkit (including licking wheel nut) present?
- What oil has been used and how often changed?
Usual stuff really - just remember its a powerful car and things do wear out of its abused and not regularly maintained. Other than that its a strong car too and is reliable if looked after.
What you seen?
J