Turbo intake and exhaust Qs

I have just bought a 2000 audi a4 1.8t quattro and I am very serious about modding this car. German cars however are much different than japanese cars so Im a nooby when it comes to audis. I was just wondering What the best turbo intake to get for my car would be ? And going along with this question, when im installing a new intake in this car can i get an intake that completely takes the place of the intake box or can I only change the the turbo intake hose because I would like to get an turbo intake with a nicer look than some box sitting there. Lastly Im in the market for an exhaust, I was wondering how good the Apexi World Sport Exhaust is performance wise because I would like to get alot out of this car, what other good exhaust systems can I get for this car that are affordable and under 800 dollars? Thank you to whoever responds.