Complex sentence: The JS2 was homologated for road use and used a Maserati V6 engine, while the JS3 was an open-top sports-prototype powered by a Cosworth DFV V8 engine.
Split into simpler sentences: The JS2 was homologated for road use and used a Maserati V6 engine. The JS3 was an open-top sports-prototype powered by a Cosworth DFV V8 engine.