The vibration in the gauge is usually the pulses from the intake valves opening. That happens when using the port next to the map sensor. If you plug into the cast intake plenum it should do away with the pressure pulses. This requires removing the intake,drilling, and tapping it for the fitting. Another way might be to restrict the flow to the boost gauge with a valve or squashing the hose just a little so the gauge still works but the pulses don't make it through.