His is vented from both sides like yours. But i even have kits out there venting one side, like mine, and they work fine. But Marios vents both sides, which is really weird. Seen a few guys forget the signal line and have the gate open high.
What do you mean by "vented from both sides"? Do you mean the wastegate? If so, then that's the problem. The gate won't open until very high boost without a reference line hooked up.