Editing phone interviews for quality/size balance.

[glvr]

Not sure if this is the place to post, but the people here clearly know what they're doing so here goes...

I have some phone conversations, recorded by an online service, which I need to edit and release in the best quality I can sensibly get.

I'm of course limited by the original files, which are mp3 files - 24kbps mono sampled at 22.05khz.

My plan is to convert copies to wav/aiff for editing, and then save to mp3 as 96kbps mono sampled at 44,100khz.

I figure this should give a sensible balance of audio quality to file size.

Questions:

1 Is there likely to be a significant difference in quality between those wav/aiff and final mp3 files?

2 Could I lower those kbps and khz rates without significant loss of quality?

3 Is there a set of filter etc actions which'll usually improve the quality of recorded phone calls?