Slight thread jack - I have a S2R800 with the fast idle. Other than the fast idle are there many signigicant differences between the stepper and what I have, or is it just a small evolution in the motor?
I wouldn't attempt to use an ECU intended for a HM or a Multi. Both of those bikes have digital speedos and will cause problems if used in your S2R1K.
You can use one designed for any 1000DS motor that has a stepper motor and an analog speedo. I have one on my bike from a sport classic. If you're unsure of which bikes have the stepper motor just look at the left handlebar controls. If there is a fast idle adjustment lever it doesn't have the stepper motor.