I've come across a shock from a XR400 for cheap that has been revalved and resprung the way I want it. The weight difference between the two bikes is 15lbs or so...Does anyone know if the rear shocks can be swapped? I emailed ohlins, they say their XR400 shock shaft is longer (???) but the 400 shock can be converted to a 600 shock. As for the OEM ones, what say you?