Charmbreaker Devils seems an ill fit for the deck. Your deck doesnt want to cast a turn 6 do nothing until the next turn card. Since it curves out at 3 with all the other cards.
If you're willing to invest in the deck I would suggest
goblin guide. It's by far the best 1 drop in red in Modern. Also
Boros Charm is a great burn/protection spell and should replace either the curse or the
show of valor since it just does more in the deck. The curse only does 1 dmg per turn and in modern you can die much earlier than Standard. Try
Skullcrack to counter life gain and monestary swiftspear for more hasty openers. Also Eidelon of the Great Revel is great in modern and you might want to consider more burn and less creatures, since modern is full of removal and less full of
counterspell that want to be used on a 1 mana burn spell (
lava spike,
shard volley,
rift bolt). Hopefully this helped