I'm new to Audi. Have to replace pre-cats that bolt onto my turbos. The expensive ones. Figured I can do this instead for a very similar price.

Will replacing the stock pre-cat and rear cat with downpiping, catpipes, and test pipes still let me pass emissions? And how much performance will this give me if I kept stock mufflers backwards on. I'm not looking to spend more than 1,500 on parts.