Good day. I been researching some tuning options in Cape Town for my X3 2.0d n47 auto. I would like to improve torque and response. This is my daily and I do regular trips seeing clients so want to stay reliable and realistic with gains. What i have found celtic tuning....wizz auto replied and gave price for sw. Wolftegnick also replied and gave price on sw. I mention these cause they took trouble to respond. The others are renzport, excede, atm and qtec. Anyone used any of these guys and have experience with them. My goal is responsiveness and torque. So figures on paper dont mean much. How the car reaponded on road more important and of course improvement in fuel consumption. Ps. How does tge plug and play works. Are they any good? Is sw better because it uses the cars ecu.