Tubro Boost Control Question?????

Im looking at buying a Greddy Profec B-Spec.2 II Electronic Boost Controller and I was just wondering what I should set my daily driving boost at and what I should set my performance boost at? Also it says it is ideal for low to high boost levels for single turbos with actuator or external wastegates. I was jsut wondering if thoser are stock on a 97 A4 1.8T or i have to get an external wastegate or actuator? Thanks