Download Why I Still use MP3 and how to compress your music library - Lame Mp3 v3.100 Encoder - 管理压缩音乐库 MP3 Song Free

Official Description & Notes

V4 is most balanced (I use this one)
V3 gives you more headroom (Cut down file size half from 320k CBR)
V2 is absolutely top ceiling (Use for special music with complexity)
V1 Not necessary (More headroom above transparency)
V0 Absurd (It has no purpose)

Software used: Mp3tag, Bulk Rename Utility, and freac.

lame setting used:
-m j -V 4 -q 0 --vbr-new -b 128

This setting is less-than 1mb larger than a typical 128k CBR, but its quality is near transparency or many times better, so instead of downloading the 128k CBR files, download the 320k CBR files, then convert it to 160k VBR. You add only 1mb to a song, but you increase its quality more than 10 times. This is the best of both worlds, but of course, this requires harder work. You get what you paid (work) for.

In short, V4 is more than enough for 90% of the music lovers; V3, if you are extra; V2 if your library is small. Storage is cheap indeed, and you can go V2 all the way. A 128GB SD card can hold about 25k V2 songs average 4 minutes long, but then with V4, you can carry around 30k songs.