There's a thread on this if you want to find more info on it. Search on "race jack" and it should come up.
I bought a Torin aluminum race jack from Pep Boys and it works great! Here's a link to it on Northern Tool:
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200313500_200313500
It raises the entire side of the boxster up so high that I can slide a jack stand under the unsupported side and drop it and do the same thing with the other side. It also slides right under the back of the car and can be used for the center jacking point in the back between the muffler and the motor.