Thinking of upgrading my team. What you think I should go with (leaning towards replacing Serperior)?

Lucario @ Life Orb
Trait: Steadfast
Nature - Timid
EV - 252 SpA, 252 Speed, 4 HP
- Dark Pulse
- Aura Sphere
- Flash Cannon
- Dragon Pulse

Sylveon @ leftovers
Trait: Cute Charm
Nature - Modest
EVs: 252 HP/ 252 SpA/ 4 SpD
- Moonblast
- Psyshock
- Shadow Ball
- Draining Kiss

Gyarados @ Leftovers
Trait: Intimidate
Nature - Jolly
EVs: 252 Atk / 4 SDef / 252 Spd
- Waterfall
- Thunderbolt
- Earthquake
- Ice Fang

Rhyperior @ Assault vest
Trait: Solid Rock
Nature - Adamant
EVs: 4 HP / 252 Atk / 252 Def
- Stone Edge
- Thunderbolt
- Earthquake
- Megahorn

Salamence @ megastone
Trait: Intimidate
Nature - Jolly
EVs: 4 HP / 252 Atk / 252 Spd
- Double Edge
- Dragon Claw
- Steel Wing
- Crunch


Serperior @ Shell Bell
Trait: Overgrow
Nature - Adamant
EVs: 252 Attack, 252 Defense, 4 HP
- Leaf Blade
- Iron Tail
- Return
- Glare