To be honest, the Touareg is not the most reliable thing around. It suffers from electrical maladies and the air suspension is prone to failure. The timing chain on the V6 engines can also be fragile. The front brakes are a bit on the small side for a car that big and heavy so check under the front for damage too. Check for a thumping sensation from the automatic gearbox when changing gears and the centre differential can be weak so listen for whining or rattling noises. They chew through tyres as well, so check for uneven or excessive wear.