Colin,
At a recent Service Workshop at PC Cambridge the subject of RMS leaks on 986 Boxster and 987 Cayman and Boxster models was discussed, but the same would apply to the 986 and 987 911-series cars.
Garry Sorrell was joined by three technicians, who between them had more than 50 years Porsche experience, and the point was made that if there is only a light oil misting in the vicinity of the crankcase/bellhousing joint then it is best just to leave well alone. However, if oil drips are present, then further investigation is advisable.
Garry also made the point that if you are in the market for a car and find one where the RMS has been replaced a number of times then beware, because this could be an indication of a more serious problem where there is a defective seal between the two crankcase halves, necessitating an engine strip-down.
On the plus side, these days they are seeing significantly fewer RMS issues in the workshop and could not recall having seen a failure on the Gen2 cars to date.
Jeff