So I am rebuilding the top end of my motor... (I'm sure you saw the previous thread) - Who is a good authority on parts for Gen 2

I don't need to go crazy, so I am thinking mostly OEM parts... but I knowI need to replace:

- Lifters
- Rockers
- Pushrods
- Springs (maybe)


I will have the heads themselves gone through... but what out of these components should I replace with better than OEM? Is it worth it?