It probably was a 2.5L Boxster engine. Those had some hideous flaws. The '98-'00 engines had porous blocks that would crack and cylinder sleeves that would slip. Later years had rear main seals that would leak like a sieve, and intermediate shaft bearings that would die. There are lots of reasons why oil would find itself suddenly outside the engine.
I researched all this when I was deciding between an '01 Boxster and an '05 Mustang GT.
I got the Mustang. After 3 years of ownership, it hasn't caught fire.