Currently vacuum, like the normal JDM cyclone manifolds. That can be changed though, many have used actuators or RPM switches either controlled via ecmlink or other to trigger (usually at 3000-4000 RPM).

For turbo, I know that plenty of people have used the original cyclone and made more power down low as it accelerates flow to the motor by blocking a portion of the intake runners when flow lacks due to low RPM/Speed. Quicker air build up in the chamber at low speed/RPM = More torque and HP per spark. This means the car becomes more nervous; more fun to drive as a daily, which is what I'm after. For bigger turbo users, it helps spool a big turbo quicker (300-400rpm quicker) for the same reason (accelerated flow). The issue with the original cyclone is that for BIG power it's not as good at the top end because of its plenum size. This rare VR4 AMG version corrects that issue with a bigger plenum. As an added bonus, less parts as it's only 2 part instead of 3 like the JDM original Cyclone Intake; which also minimizes chances of boost leak by probability.