Used on my 97 NA8 Miata. The aluminum blocks brace the bar to the frame above the mounts and prevents the larger bar from ripping the mount. Simple install and design but good results.
120$ OBO. Can sell the bar braces separately for 25$ ($35 new)
http://i1119.photobucket.com/albums/...pszqvbgnrq.jpg
http://i1119.photobucket.com/albums/...psqdrbc1sa.jpg