Welcome!
When buying any performance car its normal checks which are important. Just check it drives right. No clicking, boosts fine, no smoke everything feels 'tight'. Evidence of good service. cam belt at 45k or 5 years.
Only real thing is AYC. do some good swerving and listen for a donkey...
And possibly clutch. (an expensive consumable)
Running cost isnt as cheap as a shopping car but they aren't too bad. Very regular service and petrol is the big cost. Obviously disks, pads, clutch etc are all not cheap but you shouldnt need too many of them.