I need to edit about a six MP3 files to extract part of the music for each file. Each file is about 6 hours long, and I need to remove the last 4 hours. Since the file is already lossy, I am assuming to maintain the same sound quality it should not be recompressed. Would extracting to an uncompressed sound file, trim to the desired audio, and then recompress back to MP3 reduce the sound quality? Do some programs edit the MP3 file without recompression?

Alternatively, after editing the uncompressed sound file, I could save it as a FLAC to avoid a second lossy compression.

I am looking for something easy to use and not expensive since I have a limited one-time need.
Any software recommendations or suggestions?

Thanks in advance.