i have a 2003 audi a4 quattro. i have already put an air filer in my car and i was wondering if u would suggest to put a cold air intake in the car as well. and if i was to do an exhaust what would u suggest? and i was also thinking about putting in a different turbo kit. either a GT32 71MM 52 TRIM 520HP, GT35 71MM 52 TRIM 600 HP, GT37 76MM 52 TRIM 750HP. which would u suggest?

 

You put a filter in your stock airbox, right? therre is no hp improvement in our cars fro ma cai, only the sound.
Exhaust? its up to u, youtube will help you- all people are different, some like quite other super loud.
LOL on this turbo thread )) Sorry. just search here, you will find a lot of answers.
Ok, if u dont want to, go here https://www.audiforums.com/forum/b5-models-69/1-8t-turbo-upgrade-information-93439/