[Raceboy]

I would not take the history of failed turbocharged SC engines too seriously as pretty much none of them had controlled fuel and ignition with twin plugs. You cannot expect the engine to last without proper tune.

Regarding cast vs forged pistons. Well, let's analyze this from the prospective of single cylinder power. On standard SC (204 hp) one cylinder produces 34 hp which is ridicolous. This is in the same catgeroy of euro 924 (32 hp) and 924 has also cast pistons FYI.

Piston material treatment (=strength) is most relevant when one wants to up the revs considerably. On turbocharged STREET car it is a moot point. My turbocharged 924 (with cast pistons) has more than DOUBLE the horsepower of standard car (260 hp) and that makes 65hp per cylinder.

911 SC with that hp per cylinder is easy. Ring land failures are from detonation, either caused by bad fuel or bad CIS. It is common on other cars to with bad tune, not just SC.

I would leave the engine as is presuming that it is healthy or if you pull it apart anyway, just make a refresh and twin-plug it just like you are planning. And making sure that it is tuned well after, and you won't have any problems.

7.0 CR with modern fuel and spark management is a joke, seriously.