How to replace Audio

Hi guys.

I've very recently used Compressor to fix audio popping in FCPX. But I've done that using the full video and audio clip, in the first time I used it just last week.

It works great with full video and fixes the popping, but since that takes a while in video form when using compressor, how do I use newly upscaled Compressor Audio files, to then use those audio files and replace it with the troublesome audio in FCPX.

Replacing Audio alone seems it would save a lot of time.

As well, Since in my latest project I've got over 900 1080p video/audio files, all with audio problems in FCPX, after I use Compressor to upscale ( not sure if it's the right word ) to fix the audio files, is there a way to mass replace the audio all at once, or at least in large chunks in FCPX?

Appreciate any help.