With the new formatting rules you can now slash Mega Stones with other items. You also don't need a specific section for MEvos and you need to change your format in general:
http://www.smogon.com/forums/thread...rate-mega-evos-use-the-old-set-style.3491996/
Let's talk SpD Ttar now. Imo, Lefties, Smooth Rock, and Assault Vest should be the items slashed on the set, in the order i mentioned them. Leftovers goes first for two reasons: Tyranitar is probably the best Pokemon that gets SR atm, so not using it is honestly a sin. It also gets a ton of switch-ins against Pokemon such as Talonflame, Goodra, Noivern, Florges, Togekiss, and Sylveon (can't do much but sets up sand and SR in their face). Also, Lefties is needed to keep in check Talonflame as long as possible. Talonflame can not only wear down Tyranitar with WoW / U-turn, but it is also usually paired with anti-SR mons such as spinners or Defog users, and has Roost, all of which often make walling Talonflame for a long period and keeping SR on the field a daunting task.
Then, both Smooth Rock and Assault Vest are good options, but Smooth Rock goes first because Tyranitar is by far the best SR user and not being able to use this move sucks.
Also, give a mention to Tyranitarite in AC, as it has some situational uses on teams without ane MEvo. Mention Flamethrower in AC too, for those that hate low accuracy moves.
Oh and of course change the moveset and make it like this:
Nature: Careful / Sassy<br />
- Stealth Rock / Fire Blast<br />
- Pursuit<br />
- Crunch<br />
- Rock Slide / Fire Blast</p>
Stealth Rock, Crunch, and pursuit are obvious and don't need any explaining. Rock Slide is your best bet against Fairy-types, especially Togekiss, Talonflame, and Volcarona, letting you OHKO-2HKO most of those, so it gets the first slash on the last slot. Fire Blast is great against the very common Steel-types, as well as King's Shield Aegislash that try to get smart. Ice Beam goes to AC, because while nice to hit Gliscor, Garchomp, and Zygarder, the other moves are more useful in general. I am ok with it being slashed 3rd but i prefer it on AC. Fire Blast slashed after SR if you are using Assault Vest.
Finally, i don't like Rock Polish Tyranitar, like at all. Without an Atk boost its power is really bad, especially with Fairy-types round, and bulky physical walls such as Skarmory and Hippowdon being very common. You need the Atk boost in order to be able to get past weakened Hippowdon and OHKO Fairies with Stone Edge.
Also, i don't see the need for special attacks on this set, as Fire Fang and Ice Fang are better. Fire Fang deals more damage to Ferrothorn and Scizor, while Stone Edge already 2HKOes physically defensive Skarmory (same as Fire Blast). Similarly, Ice Fang is like Ice Beam but better after a DD boost. OHKOes Zygarde and Garchomp (which Ice Beam can't do), 3HKOes physically defensive Hippowdon (same with Ice Beam), and 2HKOes specially defensive Hippowdon (which Ice Beam can't do).