Yet another one of those programs that has too many of the same thing out there. Have been using Safari Tweaks since version 4 Safari came out of the closet. Not only does it have the same fancy way to apply terminal commands (since all of the tweaks are possible from terminal) but it has a few more than this one and the Safari Modifier. Sure it takes a file swap to get it in place, but you can access it from the Safari menu at the top. No need to launch another program and make settings. Of course with any of them you have to restart Safari.

Then if you add Safari Stand, you can get rid of that ugly dark metal look and more