RED Main Creature (Modern)

++Junk++++++

-???
+???

Take out their large size bombs with some spell like Roast or Combust.

On the play, it's possible you want Molten Rain to try and slow them down while still attacking their life total but I would not board them in on the draw.

This is one of your better matchups and swapping Helixes for Boros Charms seems reasonable as it is a better racing tool.
It also allows you to have more ways to deal with an opposing Scavenging Ooze.

If they are playing with Anafenzas along with Siege Rhino then I would also bringing in a Combust or two and cut the Shard Volleys.

++Affinity++++++

-3 Skullcrack
+3 Smash to Smithereens

Concentrate on burning while taking out the 1/1 creatures and destroying artifacts.

This is one of the most difficult matchups and you basically need to draw multiple Searing Blazes and Smash to Smithereens to win.
You want to bring in as many ways to deal with their Cranial Platings and Arcbound Ravagers.
Swapping out the non-interactive burn for interactive spells is the way to go.(meaning that the major threat are the 1/1s on the board! )

If you absolutely want to crush Affinity, Shattering Spree or Stomping Ground + Ancient Grudge could be added to the deck.
Their only way to gain life is typically Vault Skirge so the Flames and Skullcrack are mediocre here.

++Splinter Twin++++++

-4 Skullcrack
+4 (BurnCardOfChoiceThatTargetsCreatures&Players)

U/R Twin has no life gain effects so, once again, swapping out the Skullcracks and Flames of the Bloodhand for burn that can kill their Pestermites.

Most versions of Splinter Twin do not play too many Artifacts Spellskites
but if they do, bring in the Wear//Tears as it can get both Spellskite and the Enchantment Splinter Twin.

++Tron++++++

-4 Searing Blaze
-2 Ball Lightning
+3 Molten rain
+3 Smash to Smithereens

I'm not exactly sure how good Smash to Smithereens is in the matchup.
Many of their 1-mana artifacts can just be cycled if they leave up mana.
They seem better on the play to get opposing Expedition Maps on your turn 2.

Searing Blaze does almost nothing so Smash to Smithereens is the best option left.
This should be a fairly good matchup as the burn deck basically goldfishes on turn 4 and Tron does not have too many ways to disrupt your strategy.
Turn 3 Wurmcoil Engine is problematic but then you get to complain about them being incredibly lucky.

++Scapeshift++++++

-4 Searing Blaze
+3 Molten Rain
+1 (BurnCardOfChoice)

Once again, Searing Blaze does almost nothing in this matchup. They will likely be boarding in Obstinate Baloths so just be mindful of that when sequencing your burn spells.

http://www.channelfireball.com/articles/teamcfb-deck-guide-modern-red-deck-wins/