i did a quick search but the results were pretty scattered. i need to order a resonator and i need to know the stock exhust size. pretty sure its 2.25" but i just want to be sure. car is an 01' 30v a4 quattro. thanks bro-skis.

 

throughout the whole exhaust theres 3? different sizes of piping
im pretty sure you need 2.5 i used a 2.5 clamp to connect the cats to the catback

 

ha. okay. guess ill have to crawl under it and do a little measuring...