Hello fellow TT owners, this my first post so I apologize to ahead of time if this is a dumb question, the dealer said I need to replace my cabin filter, what’s the part number, where can I buy the filter and how and where do I replace the filter.

FYI! I already replaced my engine filter with a new K&N filter, car runs better now. Thanks folks. Feel free to include pictures of filter replacement.

Well of course you need to replace it. It's things like this that keep the dealership's doors open. Nevermind that we survived all those years breathing horrid, raw air from outside the car. It's a wonder any of us are still alive.

Grab a filter off eBay for ten bucks. You can even get a "charcoal" one if you're a customer for that kind of marketing, or plan on driving around Chernobyl. Pop the hood and peel up the weatherstripping on the cowl on the passenger side. It'll probably be deformed from where the last grease monkey didn't get it re-seated properly. Nestled in there under the wiper is the filter, lift up and pull toward the bumper. It has a nuisance frame on it that never quite feels right, and getting it back in place is why you seldom see Audi mechanics smiling. Be patient and somewhat gentle, and take solace in the reality that this is one operation where "good enough" really is.

http://www.wixconnect.com/assets/wixcabinairbrochure.pdf

One may also find cabin air filter replacements at Wal*Mart.  Part number for my 2001 TT is CA8644A, and yes I used to be a Fram Man!  Thanks to Guy for providing replacement information above, I look forward to it!