It is a very simple yet very useful audio editor for editing MP3 files, but changing things like volume, normalising, removing sections etc, it does so with out recompressing the MP3, so if you want to keep it as an MP3, the quality doesn't suffer when you save your changes.
A really good advanced freeware audio editor is Audacity - http://audacity.sourceforge.net/
With this method, do whatever you need to then save it to WAVE file aftery you're done, so you dont lose quality by recompressing to MP3. Then burn via NERO
Pro Tools is complete overkill, normalising and basic editing is the same whatever you use, Audacity will be just as effective. When normalising to peak, set it to peak at -0.1dB and you're sorted, that will help things alot, but each track will still be slightly different as they will have all been mastered differently and will have different RMS volume levels, and the radio will ALWAYS be louder as the radio stations but an extra compressor in their mixing chain at the end before things go out, to conserve bandwidth etc by squashing the sound as much as possible (why music on radio sounds so fatigued and nasty compared to on CD)
Hope this helps.