Although this is a review of the 987/987S, it may give you some more insight:
http://www.windingroad.com/reviews-page/porsche-boxster-and-boxster-s/
"Over the road, it’s clear the bog-standard Boxster paired with the regular five-speed and seventeen-inch wheels is the enthusiast’s best buy. Not only does the optional six-speed Tiptronic S transmission cost $3210, it also occasionally second-guesses its driver. It’s not that the uplevel S is unreasonably priced—it’s just that standard model’s intrinsic goodness is so total that it’s obviously the best value. In most situations, the S’s horsepower simply isn’t missed, and the base model feels a bit lighter on its feet to boot. Just make sure to go for the DIY cogswapper."
Good luck with whatever you decide.