I believe OPC will sell you a warranty on a car with FSH after an inspection.
they will but they will also provide you with a list of any remedial work to take it up to OPC standard before you buy the warranty.
Been there and done it myself years ago with them.
The car must also have zero modifications, N rated tyres etc etc
If it were my money and deadset on a 997 i'd keep an eye out and budget knowing it was going to need the engine done sooner or later and you might as well do the clutch while the engine has been pulled out.
Ive a mate in Dublin that has a 3.6 996 and hes on his third Porsche OPC engine.
Another common problem are the front bumper radiators corroding in them (the crap caught in the bumper intake cant escape), the window mechanisms breaking, exhausts rotting to pieces (although they would be replaced by now at this age), coil packs rotting and getting misfires, coil pack heatshields rusting through. Also the radio headunit is something from the stoneages so avoid the sat nav models and save a few ££s.