If you're editing MP3s, try mp3directcut -- it does lossless editing. With Audacity and virtually every other sound editor, if you edit an MP3 and re-save it as an MP3, it recodes the MP3, losing quality. mp3directcut lets you edit and leave the audio as-is.
A recode of an encode is a bad idea.
Indeed. Most of my ra files up until September 2007 are only 32k in the first place - you really wouldn't want to be, for example, converting a 32k ra file to a 128k mp3 then re-encoding to another 128k mp3. Would sound truly dreadful, all those compression artefacts are very hard to listen to, especially on headphones.
Frrom September 2007, the ra streams were then encoded at 64k, this is the case for the majority of the files I have until around April 2010, when I began recording the direct Freeview radio stream which are 192k mp2 - they can also be edited losslessly with mp3directcut. I have been using that program for a number of years now, can thoroughly recommend it for editing, only a small program and is very easy to use. My personal preference is to convert ra to wav, edit the wav, then save as mp3, but I guess converting ra to mp3 directly and editing the mp3 and saving with without re-encoding is pretty much the same.