Throttle being "cut-out" during its application has NOTHING to do with the weight of your flywheel and it is not normal when the DCS functions are disengaged.
The flywheel won't make the situation better. When power is lessened it is because of a change the computer makes to the spark and fuel delivery.
Changing to a lightweight flywheel will make matters worse when power is cut-out as it will make the car slow down even quicker. You'd have better results changing your dead pedal. :smile:
Again, not all e46 models have the "two-stage" (on or off) DSC button.