As Don Honchkrorleone has already suggsted great pokemon, the only change I would make is to replace Manectric with Choice Scarf Raikou. He can also absorb Electric-type attacks (if you are playing on PO) and he has higher base Special Attack and Speed, which can be crucial for turning 2HKOs into OHKOs.
Raikou @ Choice Scarf
Trait: Volt Absorb (Pressure if you are using Aura Sphere)
EVs: 4 Def / 252 SpA / 252 Spe
Modest Nature (Rash if you are using Aura Sphere)
- Hidden Power Ice
- Volt Switch
- Aura Sphere / Extrasensory