Dies to Removal

So, bringing the discussion back to Magic, my LGS has been having this tournament, called Guild Wars, where everyone builds a Legacy legal deck, but only in the 2 colors of your chosen guild, which you must stick with for the whole tournament. Your cards are also limited to your guild's color identity. This means that there are no Tier 1 decks in this tournament, although there are some very powerful ones, as well as some very interesting combo lists. You're on a team with members of your same guild, and you you can play anytime during store hours, usually just between rounds. It goes until July, and the guild with the highest win percentage at the end splits a box. I went Gruul, and just put together this cheap standard fare aggro deck.
[deck]Guild Wars
Creatures
4 Goblin Guide
4 Skyshroud Elite
4 Burning-Tree Emissary
4 Flinthoof Boar
4 Ghor-Clan Rampager
4 Bloodbraid Elf

Other Spells
n4 Rancor
4 Lightning Bolt
4 Forked Bolt
2 Gruul Charm
2 Colossal Might

Land

4 Copperline Gorge
4 Stomping Ground
5 Forest
7 Mountain[/deck]

The (incredibly shitty) board looks like this:
[deck]Sideboard
2 Red Elemental Blast
3 Ancient Grudge
3 Flame Slash
1 Gruul Charm
2 Electrickery
2 Magistrate's Veto
1 Choke
1 Sulfur Elemental[/deck]

Cards I'm considering adding:
[cards]Stormblood Berserker
Experiment One
Skarrg Guildmage
Arc Trail
Kird Ape[/cards]
Cards I'm considering cutting:
Most of the sideboard
[cards]Forked Bolt
Gruul Charm
Colossal Might[/cards]
What's the best thing that an extra $20 could do to this deck? Also, what should I do for a sideboard for a largely unknown meta limited by the fact that all decks are 2 colors?

This means that there are no Tier 1 decks in this tournament

U/R Sneak/Show and U/W Miracles are quite top tier actually

[deck]Guild Wars
Creatures
4 Goblin Guide
4 Skyshroud Elite
4 Burning-Tree Emissary
4 Flinthoof Boar
4 Ghor-Clan Rampager
4 Bloodbraid Elf

Other Spells
4 Rancor
4 Lightning Bolt
4 Forked Bolt
2 Gruul Charm
2 Colossal Might

Land

4 Copperline Gorge
4 Stomping Ground
5 Forest
7 Mountain[/deck]

The (incredibly shitty) board looks like this:
[deck]Sideboard
2 Red
Elemental Blast
3 Ancient Grudge
3 Flame Slash
1 Gruul Charm
2 Electrickery
2 Magistrate's Veto
1 Choke
1 Sulfur Elemental[/deck]

Hmm, $20 budget is a tall order, to note, is it $20 a week (like extra spending money leftover) or $20 and that's it, cause that would affect my suggestions a bit, not too much thought

First things first, things I would cut first chance you get
Blood-braid Elf
Ghor Clan Rampager
Rancor
Gruul Charm
Colossal Might

BBE: He's good, but not where you want to be in your deck, at 4 CMC he's a bit high for what you want to be doing (cheap efficient beats with removal, ala Zoo I take it?), although the cascade is nice, you should be able to Turn 4 someone with out it anyways

Ghor-Clan/Rancor/Colossal Might: In a format with things like Swords to Plowshares (that isn't EDH), these cards pretty much unplayable

Gruul Charm: What does this actually do?

That
out of the way, the creatures other than BBE and Ghorclan look like your on the right track, cheap efficient beats, if your want to go a more Zoo route, look into Kird Ape, he's a 2/3 for R if you have stomping grounds, and you can play him off a burning tree emissary, which is cool, another one you can play would be Figure of Destiny (if allowed), you can't level him sadly, but he does grow with the game and functions as a mana sink. Hidden Herd is something I've seen in recent zoo lists, if you think people are going to be playing lots of non basics (price of progress is another good one speaking of), admittedly the zoo route is a bit more expensive.

If you want to go on a more burn route, I would simply recommend looking up recent burn lists, most of the deck is fairly inexpensive (Lava Spike, Rift Bolt, Keldon Marauders, Hellspark Elemental), and would not be hard to make it R/G.

If you don't know what your up against, I'd meta for things you know you can't deal with, incidental life gain (
such as batterskull) etc, until you know what your presented with, unfortunately, that would involve a set of sulfuric vortex right at around $20, so there is that, 4 Red Elemental Blast (or Pyroblast) are never bad, people will inevitably play blue, Faerie Macabre if you think reanimator will show up, Pithing Needle if you suspect a COP:Red, etc. Pyroclasm/Searing Blaze are probably better than Eletrickery/Flame Slash for creature strategies though.

All I got right now