i got the Ohlins sidemount damper.
model sd154,
i mounted mine right above the bottom triple on the 54mm fork and other end clamps to frame tube which on my 01m900 is about 23mm diameter. perfect fit. great damper.
i got mine at spareshack uk about 2 years ago. about $us300 to 350 but dont remember exactly.not sure if sd154 would fit new S4R frame or fork tho... email me if you want to see pics of it mounted
johnbae@bemaforest.com