I did buy it used. That was my thought as well. But I checked and it passes all the tests I read to do. If you hold the brake and the gas, the revs don't go up much, and I think it won't rev up past like 4k RPM I you rev it at a standstill. Also brought it in to the dealer twice, once for warranty work (faulty shifter) and they never said anything.
If you have other suggestions on how to double check for a tune, let me know. I am planning on hitting the dyno next. But I think it's just because it's one of the lighter GTIs you can get, 2 door, no sunroof. I also think most guys go straight to a tune and don't spend much time at the drag strip stock.