Complex sentence: The Chevrolet Chevette was introduced in September, 1975 and manufactured for model years 1976-1987 based on GM's worldwide T platform and superceding the Vega as Chevrolet's entry-level subcompact.
Split into simpler sentences: The Chevrolet Chevette was introduced in September, 1975 and manufactured 1976-1987 based on GM's worldwide T platform. The Chevette superceded the Vega as Chevrolet's entry-level subcompact.