I've got the K&N panel filter on my 1.5 TSI for about half a year now. I serviced parts of the intake a week ago to see how it is doing and how much crap it accumulated. Everything is fine, it is doing its job. The intake pipes and throttle body were slightly oily but thats due to the PCV dump.
I am sure you are wondering about its performance... As the entire internet will tell you, and I can confirm that, it does not give you any game changing performance boosts. There is a slightly more aggressive tone from the intake, and I am sure it breathes easier than the OEM one, so thats a plus. I went for the panel filter since its cheaper than a full intake swap, and because I am still not sure how far I will proceede with the mods. My priority is to ensure long term health of the engine, and handling components before I start any more performance fiddling. Thats why a catch can is my next item on to-do the list so I can stop any more oily residue across the engine intake. After that maybe the brakes.
If you can find it cheaply, I would recommend it. The part number is "33-3111"
FYI, I saw your other post about the brakes. I myself have looked at EBC pads and rotors for the front, that will get to at some point in time.