[thstone]

No, the Boxster does not have a two-stage clutch. What you describe makes me think of clutch judder where the friction slip is not linear resulting in uneven take-off from a stop. Judder typically occurs when the surface of the friction plate engages the flywheel unevenly.

IF (and that's a capital IF) clutch judder is the problem, one way to adjust for this in the short term is exactly what you've been doing: apply a smooth increase in throttle as you let the clutch out and avoid slipping the clutch any more than necessary. The throttle and the clutch actions should be smooth, linear, and nicely timed. In the long tern, the problem will get progressively worse and the clutch will likely need repair.