Also could you Excadrill/Tyranitar users check if the things below are correct and answer whats missing for Excadrill's evs. Firstly Ivs, now I want them competitive but I don't mind if they aren't completely perfect so I assume these Ivs are what need to be perfect:
Tyranitar - Hp, atk, def, sp.D Excadrill - atk, Spd
I am assuming you are running Sand Rush on Excadrill, and thus you would want max speed and attack.
I agree that Earthquake is oing to wreck them, but with the auto-sandstorm and excadrill's sand rush (and maybe choice scarf on ttar with max speed), you might outspeed most things anyway (especially things that would have earthquake on them).
It would be an interesting experiment, but I don't know if it would ultimately be worth it.