ok guys i know there are lots and lots of threads on this but i need a definitive answer . my s3 (2001 facelift) is running standard exhaust cat etc , it has been chipped. what i want to know is which is the best make and price for a full downpipe , sport cat and cat back exhaust . i dont want it to be load (infact the same as standard would be nice). also do i need to do all of it to get a good airflow or can i just get downpipe and cat or just cat back ? all help welcome guys .