[Adam]

There is no exact RPM someone can tell you because of all the different variables. Tires, temp(tire and ambient), and pavement surface are just a few big factors that affect a launch. When I autocross and launch the car at the start I vary rpms depending on those factors mainly and use 2.5k-4.5k launches typically. Wheelspin = slow plus with the boxster it usually = wheel hop so try to minimize both. Don't slip the clutch too much, but don't treat it like an on/off switch either.