one suggestion, as to potholes & planks, is to stand up while going over either, or any other objects on the road, as instructed by the msf. this allows the bike to absorb shock more independent from your body.
downshifting is actually suggested when slowing down. the jumps are normal when downshifting; the key is to feather the clutch to smooth out such jumps. generally, the higher the rpm (when decreasing speed), the slower the release should be (& vice versa).
