I'm going for the S purely for the 3.8 and the extra power (unless I get my mythical GT3 drive sometime soon and I change my mind). I'll probably add the no cost sports suspension and the sports exhaust + sunroof and a few low cost other options. Apart from the power hike, if you can live without that you can save yourself a tidy bundle going for the normal Carrera. I don't think there's much in it. If I was forced to go for the cheaper car due to financial circumstances I'd hardly be worried about it, they're both lovely cars!! A few tenths of a second here or there won't alter the fact it's a new 911.