Try starting it from cold, so you can listen out for any Cambelt tensioner chirp..
Try driving in 6th and flooring the throttle to check the cluch..
Visual checks of Brake pads and discs..
Most important, check the Vin numbers and perhaps do you own Check on vw's database for service and warranty history..
Service History being Plentyfull. Check wear of things like Pedals, steering wheel for hand and foot wear to indicate usage that tallys with its mileage.
Tire wear, check for even balance of wear across the tread.
Usual oil levels and pop off the oil filler and check for signs of the oils quality.
Remember to try slow full lock in 1st and Reverse, to check for any signs of knocking..(Steering rack issues)
Just a few to check on...
hth