Designed for the ND Miata, however fits Fiat 124 too! Engineered to work with and match Good-Win Racing's Multi-Point Front Shock Brace, this rear brace is strong and IMHO a great looking piece of hardware. Using strong oval honeycomb section aluminum tubing this bar ties the tops of the rear shock towers together for better chassis rigidity. Instructions in Good-Win Racing's forum, and uses factory hardware already in the car.
http://www.good-win-racing.com/Mazda-Performance-Part/61-1840F.html
http://www.good-win-racing.com/Mazda-Performance-Part/61-1840F.html