I would go for thundurus.
Thundurus-T @ Life Orb/Choice Scarf
Trait: Volt Absorb
Evs: 4 Hp 252 Special attack 252 speed
Timid/Modest Nature
• Thunderbolt
• Gras Knot
• Hidden Power Fire/Focus Blast
• Agility/Focus blast/ Hidden Power Fire
Thundurus-I @ Leftover
Trait: Prankster
Evs: 248 HP 252 Special defense 8 Special Attack
Bold Nature (Whichever one that raises special defense and lowers attack XP)
• Thunderbolt
• Roost/Protect
• Thunderwave/Toxic
• Substitute
Chooser either, they both are great.