When getting a new P/S/R for the WS7 know that there are 2 different sets avail. RBD01143-WS7, and RBD01143-WS7/M. The /M part is the new sleeve that has the MES exhaust porting so it has 3 exhaust ports rather than 1. I know on the C6 the exhaust port on the case it's self has some shaving done to the case so the two MES ports are open to the port on the case. The part number on the WS7/WS9 crank cases match up so I assume they are the same but it's possible there was just a running change done to open this up. I will look at my old WS7II later today and make sure the MES sleeve will work fine in the older engines.