i have a 97 audi a4 1.8tq with 158k miles on it. i haven't done any upgrades to it. however, i do want to do some modifications, but i don't know where to get started. also, is it worth doing anything to it since it has so many miles?

 

Depends on how strong the motor still is. and in real #'s not just you think it feels strong. Then start here. https://www.audiforums.com/forum/audi-a4-8/newbie-guide-version-2-a-80968/