The most important thing to check on the TSI CCZA engine is that the timing chain tensioner has been updated. There's a big thread at the top of this section about failures that I suggest you have a brief look at.
Briefly, the tensioner can fail and the chain slips causing piston and valves to collide with repair bills up to thousands if you need a new engine.
Speak to the seller and find out if he knows if it has been done with the paperwork to back it up. If not then you need to allow for the cost of replacing the tensioner when you make an offer. I had my chain and tensioner replaced at a cost of £650.