To split large MP3 files in CUE-sheet points, a full CD into its tracks, you can use the CUE Splitter.

To rip your CDs (convert them to MP3) use Exact Audio Copy, a trustworthy CD ripper. If you need to convert them to Variable Bit Rate, Exact Audio Copy will do that too.

Making a playlist for a CD or for other uses, with source files coming from various recordings, difference in volume levels may be a problem. You can use MP3Gain to permanently bring all your mp3s to the same volume level (normalize them). To do the same with wavs, use WaveGain.

When you need to split or trim large audio files, Mp3DirectCut will let you cut, copy, paste or change the volume without re-encoding. It can handle Cue sheets allowing to split a file at cue positions. Pause detection sets cues or cuts to gaps of to a definable length and level. If you are extracting albw files (album wrap) try MakeItOne Album Maker, an application designed to do that. If you prefer to manually cut your file, consider using mp3extractor. To cut wav files, use Wave Splitter.

Sometimes MP3 vbr files may report wrong length. You can fix this using VbrFix.