There's no reason not to run 8 Speed though. 8 EVs in defense will accomplish nothing (it basically provides an inconsequential boost to defense) while the 8 evs guarantee that you outspeed Adamant natured Aggron. Yes, they're rare (i'd say practically non-existent) the guaranteed insurance of outspeeding Adamant Aggron is still a good thing to have on hand. (and its one Milotics best niches over other bulky water-types actually).
I'm going to test Resttalk (i'm kind of doubting its legitimacy)