Custom F6 engine design offers the advantages of tailored specifications, performance optimization, and exclusivity, catering to specific needs or applications that may not be met by mass-produced engines. However, it tends to be more costly and time-consuming due to lower economies of scale, individualized manufacturing processes, and potential challenges in sourcing unique parts. Mass-produced engines benefit from cost efficiency, faster production times, consistent quality due to standardized processes, and readily available spare parts. The limitation is less flexibility in meeting unique requirements.