RMT- SInnoh Smash

Oh dear. I can see numerous problems with this team. First of all, may I ask a question: What tier are you using this for? You mentioned 3v3 singles (sort of like battlespot) and doubles, but you weren't clear which.

 

its pretty good for a shinnoh only team

 

Oh ok, Battlespot it is. That being said, apart from your Garchomp, everything else's movesets are subpar, and even then I'd pick Fire Blast over Iron Tail since megachomp has a workable spA.

I dont understand what you want to do with your Empoleon; if you wanted an all-out attacker IMO Tail Glow Manaphy does better. Hydrocannon is a pitifully bad move since it wastes two turns. You're better off using two Scalds in a row rather than a Hydrocannon since that does more damage and has a chance to burn. Replace Blizzard for Ice Beam since the latter is more consistent. Lastly, remove Drill Peck because Empoleon's attack is poor, not to mention you run Modest. Ice Beam/Scald hits anything you want to hit with Drill Peck anyway. You're better off running Toxic or Roar since Empoleon has the bulk and resists to utilize it.

Since Battlespot is a fast meta, you're better off making Staraptor a nuke. I suggest using Choice Band or Scarf and changing its ability to Reckless, since Reckless Brave Birds dent anything that doesn't resist it, if not OHKO'ed. Remove Giga Impact and Fly, they do nothing but lose you momentum. I suggest replacing Giga Impact with Return/Double Edge and Fly with U-turn.

I suggest removing Toxic on Toxicroak, you can't really capitalize it with his frail defenses. Consider Running Gunk Shot/Drain Punch/Suckerpunch/Swords Dance or Drain Punch/Ice Punch/Gunk Shot or Poison Jab/Suckerpunch. Black Sludge is also an option for passive recovery.

Luxray is bad and is a waste of your team slots. Elemental fangs aren't good for damage, and you're better off using Rotom-W or Magnezone for electric mons.

Dusknoir just doesn't fit with your team either, since all your mons don't need Trick Room support and if you go the stall route, Dusclops is arguably better. Since you seem to be using an all-sinnoh team, consider running Mega Lucario instead and you may opt to change your mega garchomp into a scarfchomp or rockyhelmet+roughskin chomp.