Woah there.
Jolteon with Modest can't have 361 Spd...
It can only have 359 :3
But really, it depends on what you need for your team. For a powerful attacker that can make dents in the opposing teams, go with Choice Specs Thundurus.
Choice Specs Jolteon hits hard, but is more of a revenge killer. So if you want Speed, go with Jolteon.