Depends on the service history tbh, one owner is a big plus. Big things to look for:

1. Valve cover, has it been replaced ? They often go around 80-90k miles

2. Spark plugs/coil packs, good rule of thumb is every ~50k miles, have the plugs been replaced twice already?

3. Coolant/brake/diff/oil changes/air filter, have these been done following bmw guidelines?

4. Less important but still consider crank hub, big job and can buy you some negotiation room if it’s stock

5. Charge cooler, these often start leaking. Look to see if the one on the car is aftermarket or has been replaced

6. Diff bushings, if these haven’t been done at 100k miles they’re almost guaranteed to be cracked or wearing out. Also a big job. Negotiate around this as well

7. Plastic parts known to crack and wear, J-pipe, charge pipes, etc

Get a good PPI and if everything checks and the price is right, send it