 Is more always better? Of course it is! Try to remember some of the basics of CQC. Which is why you might need a three-port boost control solenoid instead of just two-port. But what's the difference? A two-port works as a bleed system. It plays but a scratch. The layout looks like this. You have one hose coming from the boost source on the compressor housing. That line runs towards the wastegate actuator. But along the way, there's a T fitting. A hose runs from that fitting to the two-port solenoid. Then the other port on the solenoid has a line running back to the intake system. Also, there's typically a small boost pill found in the line prior to the T. That serves to restrict airflow and reduce the pressure that the solenoid needs to bleed. The presence of this boost pill is very important to the function of a two-port setup. A three-port functions as an interrupt system. I ain't got time to bleed. It starts the same. A hose runs from the boost source but does not head toward the wastegate. And there is no T fitting or boost pill. An unrestricted hose runs directly to the solenoid. At that point, the solenoid interrupts the air. As the solenoid opens and closes at a rapid rate, air pressure is either bled away back to the intake or allowed to build within this line running to the wastegate actuator. At the end of the day, the purpose of a boost control solenoid is to help the wastegate do its job. The wastegate's job is to open and close by specific amounts to manage the exhaust flow through or around the turbo. For stock cars, a two-port does its job pretty well. With modified cars at a higher boost level, a three-port gives a custom tuner more direct control over the wastegate, especially when trying to maintain peak boost. What? Why would I do that?