I think I'm going to get the eurocode testpipe. In my B6 a4 turbo, all stock running synthetic oil should I go with the 3' or get one smaller? I'm sure many of you have installed these before, and it can't be too hard. Does anyone know where or have detailed instructions on how to remove the cat and how to install the eurocode testpipe included 02 sensors. I don't want to mess this up, its my first mod, and first audi. Thanks all.