SR stock boost control setup

Hello everyone, just a noob question:
On my SR the boost control hose is connected directly from wastegate to the turbo air outlet, just the way it is usually on ka-t setup. However, the stock SR setup connects the hose to engine air system, so the wastegate is actuated by the ECU, rather than directly by level of boost pressure. This way it gives more stable boost, and, as I understand, the wastegate is actuated ahead of any excess boost level, making it more stable. Does anyone have an insight to that, as well where can I get info and pics on factory SR boost control system?

Thx