I'd look for all the normal stuff on a car of that age but niggles and specifics for the tdi130 I can think of and have happened to mine are:
Torquey engine so expect worn engine mounts, feels like play in the drive train in the lower gears.
Clunking from the suspension, expecially the rear, not uncommon, usualy bushes or topmounts.
Vibration/groaning from the engine under load, usualy rattling intercooler pipe (see respective post in this forum).
Tempremental immobilizer, sometimes stops you from starting car. Sometimes diagnosed as a failed dash unit which can be £££ to replace.
Rattles from the interior - it's an
Ibiza.
Erm... anyone else?