1.4 TSI can suffer from misfires - check the ECU has been re-flashed by VW.
R's cam follower can fail, so check service records for evidence of a new one within the last 20,000 miles.
Cambelt needed on 2.0-litre petrol at 80,000 miles along with water pump and tensioner.
PCV can fail and cause rough running on 2.0-litre TSI.
Clutch can slip when engine is tuned - uprated clutch is £550 plus fitting.
DSG Mechatronic unit fails - £900 to replace.
Check tyre wear for signs of misaligned suspension.
Listen for a hum from rear end at higher speeds that points to suspension being out of line.
Mismatched panel colours show up poor crash repairs.
Door windows can freeze to rubbers.
Rear hatch struts rusted on early cars and should have been replaced by now.
Cabin wear well so be suspicious of cars with worn steering wheels and seat bolsters but low mileages.