yes correct the mission is a 6" travel bike. what the rp23 has over the rp2 is the 3 levels of propedal. the more aggressive the level, the closer you are to a lock out. the amount of travel a shock gives is dependent on the frame. the mission was designed for 6" travel with a 2" stroke shock. BUT if you put a shock that's too short (eye to eye) on, your bike geometry would change. if you put on a shock that has less stroke than your stock one, you will also get less travel due to a sooner bottom out. either situation is not healthy for you or your bike.