The Cosmo was Mazda’s largest rotary-powered coupe, based on the LA series Mazda Luce. It was available with the 12A and 13B engines. The Mazda RX-5 is easily the most unloved “RX” car ever sold. Despite all its shortcomings and subsequent unpopularity, however, this Japanese owner managed to build a classy one that appears mostly stock, albeit slammed.