The legs are part of a set, you shouldnt be switching out a set, and anyway if your really that desperate for haste spend your valor on something else, i'd say the 4set was far more important when you factor in its basically 125 more spirit on every resto gear setpiece. you can get your haste from other places and once your at 2005, you dont really need any more.
It may be itemised but they are not BiS for a setup