I understand, thank you. Do the s550 pedal electronics plug into the s197 harness? And does the s197 clutch master cylinder work with the s550 pedals?Booster has studs that pass through the firewall and marry to the pedal support, nuts secure it all together. There are additional mounting bolts that secure the back end of the pedal support (Closest to the driver) to the car inside. These mount points are different from S197 to S550 so adding some rivnuts to accept the bolts in the correct location is needed. See picture of S550 pedal assembly, you can see the 4 vertical mount holes for the booster studs and two of the 4 horizontal holes, the other two are by the clutch location. These holes are over size so there is a little tolerance for locating the added rivnuts or other mounting nuts you may use.