From the LAME wiki:
http://wiki.hydrogenaudio.org/index.php?title=LAME

In the short answer section, target bitrates for the -Vx settings (from -V0 to -V6) are listed as:
~ 230, 210, 190, 170, 155, 130, and 115 kbps.

In the long answer section (and in Foobar), the same -Vx settings list the following target bitrates:
~ 245, 225, 190, 175, 165, 130, and 115 kbps.

Which one is correct for 3.98?

If it helps, I'm part-way through encoding my library at -V4, and the average bitrate so far for ~1200 songs (mostly pop/rock) is 153kbps.

I didn't search for the thread, but I remember reading that someone was going to raise the target bitrates with latest release, so I think you should go with the higher numbers.

Bob

The "Detailed explanation (long answer)" section is the correct one, it was recently updated by CiTay and I've since updated the short answer section to mirror the long answer section. I have also updated the technical details table to reflect the changes as well.