So I'm planning on getting a 42 draft designs cat-back exhaust for my '02 225 TT. But I was reading about it and it shows these
Fitment Details

Fits 2000-2006 Audi TT 180 Quattro
Fits 2001-2006 Audi TT 225 Quattro
Bolts to our 3" downpipes using included hardware
Adjustable flanges allow for precise fitment on every TT


So I am wondering if I would need to buy one of these proir to getting this exhaust system.
Exhaust: Audi TT 225 3" Cat-back
Downpipes: 42 Draft Designs

 

No they have clamps that will do the adjustment from your stock down pipe to your 42DD exhaust.. but if you can get the down pipe as well You can benefit with more power gains / sound / and labor cost and time
Shoot me an email I can help......

 

Above is my blueflame catback installed. at the left is the OEM pipe (old dirty looking) and to the right is the bf. note the join: you need a sleeve or some other pipe connection to marry the two as the OEM is smaller in diameter than the catback.

If their's is designed to "bolt-up", you will need something to attach to your OEM end, that will bolt to thieir flanged-end, as the OEM end is just a pipe.

 

just installed a borla cat back on my 01 TT 225HP quattro perfect fit, just separate at connector and disconnect rubber hangars, one piece, borla system is 2 pieces all 304 forever stainless, even includes 1 stainless clamp,and much lighter, be aware of cheaper mild steel coated or not will not last, my 01 jetta system of 304 stainless tarnished but solid after 10 yrs make sure you get the 2.5" system for the 225hp

 

below 80K on it and going on 7 years old



tips and underneath BORLA.....

 

below 80K on it and going on 7 years old



tips and underneath BORLA.....

 

after some time trying to get the tips matched i am ready to give up, as noted it went on good bit the muffler is cocked as are the tips! thought i could adjust it but not!!!