Here's a review between the Solstice GXP and
2006 Boxster.
http://www.caranddriver.com/comparisons/11605/2007-pontiac-solstice-gxp-vs-2006-porsche-boxster.html
Despite having more power and torque, it only beats it in the 1/4 mile by .1 second..
It beat the Box on the road course (somehow...)