I also have a 16 valve that I had a Remus exhaust and a Bekkers big bore throttle body installed. I seem to agree the Adrian when the car needs to be richened up. I have a basic understanding about the Bosch system. Any adjustments will change the parameters,ie fuel/air at idle and fuel/air at speed. With the mods installed, the car went quite lean. My mechanic hooked up the Lambda sensor and we saw it reading close to 14 on the gauge. This was quite lean since the car was hesitating quite a bit at idle and when you pressed the gas to start off. He adjusted the idle fuel/air mixture, and now it reads about 2 on the scale. However, the car idles smoothly, +- 200 rpm at 1000 rpm. The 190 2.3 16 valve has never had a rock solid idle speed as it is a factory built race car at heart. Joe