Complex sentence: The cars featured exterior styling by Robert Opron, director of Renault Styling, and interior design by AMC's Richard Teague--with both the Alliance two-door sedan and the convertible body styles uniquely developed by AMC.
Split into simpler sentences: The cars featured exterior styling by Robert Opron, director of Renault Styling. The interior design was by AMC's Richard Teague, with both the Alliance two-door sedan and the convertible body styles were unique models developed by AMC.