Healthy...No!
It is best to stay under 4k RPM until the car has heated up to 180°. So you could accelerate slowly to 100mph without any problems. But I see no reason why you would want to do that. I wouldn't want to unnecessarily beat on my Boxster especially when that can easily lead to a pricey engine replacement.
Just wait the few extra minutes for the car to heat up, then rev it up to 6k+.
