Complex & High Performance Endorsement
If you want to fly bigger, faster, more powerful airplanes you will need either a high performance or complex endorsement, or both. Prior to 1997, the FAA made no distinction between high performance airplanes (those with engines larger than 200 HP) and complex airplanes (those with a constant speed propeller, retractable landing gear, and flaps). However, due to airplane accidents caused by pilots not skilled in the higher workloads involved in flying complex airplanes, the FAA has since required separate high performance and complex endorsements.
Depending on what you want to fly, you might need both a high performance and complex endorsement, which gives you the ability to fly most airplanes regardless of their horsepower or configuration. Although the time needed can vary widely depending on the airplane and avionics chosen, most high performance or complex endorsements take about 5 hours of flight time consisting of two separate flights and about 3 hours of ground time.