I agree with MNBoxster about the standard, the older the car, the more problems you will see. If I had to do it all over again, I'd buy the standard. If I wanted more overtaking power I'd get an STI. I just wanted a fun car to haul around in on weekends with the top down. But I noticed that you said you would AutoX your box so the S may be for you (IMO, a good driver in a standard could whip a sorry driver in an S, depends on the driver at AutoX). If you decide to get a box, almost every problem that has occurred in the car has a fix for it on the internet. and ppl on these forums are very knowledgable and can point to in the right direction for a DIY. Boxsters are dependable and will last but ALL boxsters have problems, it's just a matter of how much of a DIYer you are to fix it. The standard will give you just as many smiles as an S would.
porsche always makes something alittle better to charge more, just depends on how much more you want to spend, all are good. besides who buys a porsche to resale it? I bought mine to drive it til it dies.