I'm still waiting to hear about an OFFICIALLY confirmed RMS issue on the 997 Carrera S engine (M97). So far, nobody was able to put convincing facts on the table, just speculations, gossip, rumours which have travelled from one person to another and so on.

And although it seems that the RMS leakage was a serious issue on the 996, it actually wasn't. Affected cars didn't brake down spontaneously, they were still "driveable" and so far I owned two 996 (one C2 and one C4 with powerkit) and none had the RMS issue. I also personally know a lot of 996 owners and none of them had such an issue.
Meaning: it might not be as common as people think but of course I wouldn't like to see it happening on the 997 Carrera S engine (M97). This would REALLY be a shame.