I've been the third owner twice. Never knew the circumstances of the first owner in either case. Both purchases from private second owners who were selling for lifestyle reasons. Both dead on reliable cars.
Parking lot accidents can be meaningless. I had a slow speed rear-ender that creased my back bumper...nothing more. Repaired right would that affect the car's value? No. Even had a rear-ender on the highway that took out the bumper, bumperettes, and bumper supports. No sheet metal damage or electrical damage and all was repaired right. No real affect on the value of the car. The trick is to know what happened and how fixed.
And by all means drive many, select one, pay for the pre-purchase-inspection by the most knowledgeable Porsche mechanic around.
I know of no big difference in reliability between 2000-2004 model years despite what consumer reports says...too small a self selecting sample.
What I know about buying one is in these 10 articles
https://sites.google.com/site/mikefocke2/mikesporscheboxsterwebpages