I wouldnt worry about a higher mileage soop providing the price really reflects it or certain major jobs have been carried out so you dont have to potentially bare the bill.
156k on mine, original engine,turbos gearbox, BPU 1.2 bar no blue smoke oil Change every 4-5 k
Now heres the bad bit, things i would look for all from personal experience= Valve stem oil seals usually around 100k, didnt show up on mine though till i went BPU and removed both cats i then started to get little puffs of blue smoke on start up and pulling away from stand still.
Wishbones front and rear look for tramlining and general sloppy suspension and handling,
Have the brakes well checked over, as today i have just had to have both front calipers replaced as they were partially seized.
Theres probably other things that will be brought to light by the other veteran soop owners but these are just the things i have experienced in the last 5 years of ownership, then again i do considerable amount of mileage in mine between 15-20k a year and it has never let me down once and left me at the side of the road. How many other cars running 400+ bhp could achieve that at these mileages.
Happy soop hunting bud.
Chris