ill see how i go for the moment.
boost is ECU controlled mate, there is a solanoid that controls the bypass to the actuator. sometimes its good to retain the factory boost control as it can drop off boost levels in the event of detonation. that brass restrictor slows down how quickly the boost comes on, yes it does affect boost a little. on SR20s if you removed it, you got a psi or 2 more and boost came on a lot faster (compared to factory)