Not bragging at all, but I just picked up a 2001 "S" from Cali, pretty well loaded for $12750(no dents and 58k miles). I know my price was unusually low but I found someone in need of money more than their Porsche. Even on ebay there are steals all over. I would hold off for one that has a better history. What the car you are talking about has been through would scare the hell out of me.
I wouldn't touch it for no more than $9000 to $10,000. You can find "S" all day long for around $15k to $16k that has been giving tender loving care by its owner. If you look long enough (usually less than a month) you will find the steals, especially in this economy. Check craigs list in Cali(especially sacremento), as the economy has destroyed that area. I know its 4k or 5k more, but you could spend that easily if this one starts falling apart.
Some examples: (I haven't gone over the details yet) now this is a dealer and they usually are 2 to 4k higher
http://cgi.ebay.com/ebaymotors/2002-PORSCHE-BOXSTER-S-ROADSTER-6-SPEED-17RIMS-BOSE-CD_W0QQitemZ360169784093QQcmdZViewItemQQptZUS_Cars _Trucks?hash=item53dbcac31d&_trksid=p4506.c0.m245&_trkparms=65%3A1%7C39%3A1
This isn't an "s" but looks real nice. (you may need to log into ebay to view the completed auctions, but that is a good sign of what they are going for. Just look for the green prices( means sold) and check out the buy it now price. You can even email them and make them an offer if it has already closed and wasn't sold.
http://cgi.ebay.com/ebaymotors/2001-Porsche-Boxster-Silver-Manual-Premium-Sound_W0QQitemZ250460709833QQcmdZViewItemQQptZUS_C ars_Trucks?hash=item3a509f23c9&_trksid=p4506.c0.m245&_trkparms=65%3A13%7C39%3A1