[BoxsterSteve]

It seems you have started already!
As far as determining engine health, cut open the oil filter to check for metal debris, and have a local Indy check cam deviations with a Durametric.
If You don't find anything scary, start on the usual deferred maintenance items; brake fluid, coolant flush, trans fluid replacement, clean rads, oil change, serpentine belt and plugs. Check CV boots for tears if it's a stick too as they get more abuse on an S model than a base.
I have done all this maintenance on mine since buying it except the IMSR and the CV boots.
They really aren't that hard to work on and you get to save $$ on labour too.
Congratulations and have fun with that Boxster.