Mac plugins go here:
~/Library/Application Support/SketchUp 2020/SketchUp/Plugins/
I found it on SketchUcation here. The original had .rbs scrambled files, no compiled code, but must have had something incompatible with versions newer than SketchUp 8.
I also found a version that someone had rewritten for SketchUp 2015 here:
http://www.sketchando.net/descargas/plugins/FerrariSketch1.1v2015.rar