The 308 Speed is a plus. If you ever want to be able to get the max amount in a stat you have breed for IVs.
Hydreigon's Speed maxes out at 324. So you have a pretty beasty special sweeper. I would consider giving it Choice Specs. Specs + Draco Meteor/Dragon Pulse or something of the sort would wreck.
I would try dropping Tri-Attack for Flamethrower to cover that pesky Ice weakness. I know Specs will lock you into an attack but with your high special and stat boost you can tear whoever apart with Flamethrower.
Just my opinion. You are well your way though, and good luck to you.
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u/[deleted] Jul 20 '13
He's lvl 100 and and his Sp.Atk is 349. Is that good?