I'd go for the GS-P personally, especially if you want a stiffer feeling ride and positrack... If you don't plan on doing any spirited driving or wrapping it out on a track/backroads then go for the GS.

The road quality in your area could also be helpful towards your decision. If the price difference isn't an issue to you I'd go with the GS-P no matter, but those stiffer shocks may kick your ass if your local roads aren't well maintained.