I realize that this was posted in the FAQ but it did not answer my question.

I have mp3s at different bit rates, I would like to convert all my mp3s to VBR.
Is there is a lossless way to accomplish this conversion that will preserve the tags and directory structure?

Thanks.

this is the problem of transcoding.

never convert lossy formats. that will harm your music. there is no "lossless" way to do so.

Any reencoding of MP3s will lower their quality.

No. Not maybe no. Absolutely no. Only people who would tell you otherwise will be trying to sell you something. The only benefit may be that you'll be able to sell photos of your expressions to replace these... :'(

If you have the original music (such as CDs that were not created with MP3s, OGGs, MP2s, WMAs, etc. as their source), you can rerip them. That would be lossless. But that doesn't seem to be what you want.

You should leave them the way they are now.
Any additional encoding to those MP3 will only act against whatever quality they have now.
You should not attempt to convert to any other formats. Doing so WILL NOT help.