need help with vgc '15 team

[Marcusube]

Gardevoir-Mega @ Gardevoirite
Ability: Pixilate
Level: 50
EVs: 76 HP / 180 Def / 252 SpA
Modest Nature
- Protect
- Hyper Voice
- Psyshock
- Shadow Ball

Rotom-Heat @ Sitrus Berry
Ability: Levitate
Level: 50
EVs: 188 HP / 108 Def / 16 SpA / 196 SpD
Calm Nature
IVs: 0 Atk
- Will-O-Wisp
- Overheat
- Thunderbolt
- Protect

Garchomp @ Rocky Helmet
Ability: Rough Skin
Level: 50
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Protect
- Rock Slide
- Dragon Claw
- Earthquake

Greninja @ Life Orb
Ability: Protean
Level: 50
EVs: 20 Atk / 236 SpA / 252 Spe
Hasty Nature
- Ice Beam
- Protect
- Gunk Shot
- Low Kick

Suicune @ Leftovers
Ability: Pressure
Level: 50
EVs: 252 HP / 132 Def / 124 SpD
Bold Nature
- Tailwind
- Protect
- Snarl
- Scald

Whimsicott @ Focus Sash
Ability: Prankster
Level: 50
EVs: 248 HP / 8 SpA / 252 Spe
Timid Nature
- Taunt
- Encore
- Protect
- Moonblast