Mikey, Boxsters have major oil pump issues, apparently their is, an audible way of detecting the fault, but its not a run of the mill diagnosis, pump failure will render the engine scrap, due to the massive cost of repair, second hand units are like Hens teeth, or stolen!
You need to speak to an independent Porsche specialist to learn the ins and outs,
I'd also get an independent engineers report on any car your serious about...
Out of all the Boxsters I've come across over the years, I cant remember one that I'd consider owning! theirs an awful lot of sh!te out there
Thom