[Perfectlap]

depending on which standard Boxster you are comparing to an S, 40-60 additional horsepower is plenty difference to affect gas mileage. Not necessarily because it consumes more gas but because if you like sportscars you will be using that extra power. I can go through 1/4 tank without even blinking on jaunt into NYC which includes going on a highway where there is literraly no speed limit(only two lanes on a elevated highway) for ten miles and then the crazy 'lanes mean nothing' traffic once into NYC. Here in the city the traffic lights are timed in sync and almost encourage you go fast to keep the flow moving in waves.
Those yellow cabs have no chance against my S in third gear. Just don't put gas into your any where near NYC, its marked up 20-30 cents a gallon.

p.s. if you have the funds for the S don't even hesistate, you will regret it later.
"The Boxster S ($50K) and the Carrera GT ($600K) are the most balanced cars Porsche has an offer"-an Excellence contributor.