The most common reason for investing in an external wastegate is fitting an after-market turbo or better control of the boost and consequently the power output of your engine. Additionally, most large frame turbochargers are not equipped with internal wastegate systems.
Most tuners will recommend an external wastegate for any engine producing 400hp or more, as running high boost through a factory internal wastegate can overpower the actuator spring, limiting maximum boost level.
Aftermarket external wastegates feature bigger inlet and outlet ports, higher pressure springs and bigger actuator diaphragms to effectively control high boost pressure.
Gen-V is the latest Turbosmart wastegates and feature a unique collar-locking system, variable actuator cap and base, strap-type V-band clamps, liquid-cooling, 1/8″ NPT ports, and are provided with a range of springs.