Which standalone mobi metadata editor should I use?

I want to modify a book that has typos and formatting issues by doing the following:
1. Unpack the original mobi file with KindleUnpack
2. Make modifications as necessary with the source files
3. Repack the source files with Kindlegen
4. Change the metadata of the new mobi file so that its meta would be as close as possible with the original mobi file

I have completed step 1 to 3. What software should I use for step 4? I don't want to use Calibre since it makes too many hidden changes in the background that I don't want. I just want a simple software that would let me fine tune the metadata.