Complex sentence: These handmade vehicles were the brainchild of Dan Panoz who had purchased the rights to the frame designed by Frank Costin used in a defunct Irish sportscar called the TMC Costin.
Split into simpler sentences: These handmade vehicles were the brainchild of Dan Panoz. Mr. Panoz had purchased the rights to the frame designed by Frank Costin used in a defunct Irish sportscar called a TMC Costin.