I am looking for the EV items location in X. I am also super training, but I heard that If you have a power item and the pokerus you can get up to 50 EVs in a single horde encounter. I am speed EV training but the Power Items description say E.g. "Promotes HP but lowers speed" Is this "lowered" speed, speed in-battle or your Pokemon's speed in decreased when you level up?
They are found in the Battle Maison, which is in Kiloude City. You have to buy them from the attendant on the left for 16 BP each(96 for all 6). The items only lower your in battle speed. A good trick for ev training is to have the Pokemon your ev training in the back of your party holding the item needed and having the Exp Share on, as it also shares evs gained.