If you'r making a sand stream team you should DEFINITELY use Exadrill with sand rush, cause increases it's speed to something freaky :D
Id leave your last slot for something like corsela (maybe, IDK) to counter fire and stop water types for a bit
BTW i have a zoroak that has near perfect IV's and EV's which I don't use anymore, but is a great annoyer if teamed up with gengar :D