I see a very solid foundation, but see some things you can definitely change. For one, it would be a relatively easy change to go to UR Delver Burn - which you may not want to do, just throwing it out there as it is one of the most powerful decks in play right now.

Regardless, I would ditch Dark Confidant for Treasure Cruise. Just all around better card advantage, and Reid Duke recently remarked that Cruise effectively killed Bob.

I like Monastery Swiftspear here instead of 4 Goblin Guides - maybe 50/50 for them or even just take out 4 Bob and put in 4 Spears and that would round it out a bit. Also, I think splashing white for some Path to Exile in side with Boros Charm mainboard.

Swiftspear and Pyromancer really don't belong in Burn/RDW, as they fit in more of a Tempo shell. You're not running counterspells or trying to draw the game out, on the contrary you want to close the game ASAP.

That being said, cut Young Pyromancer for Eidolon of the Great Revel and cut Blightning for Vexing Devil. Consider cutting Monastery Swiftspear for Goblin Guide.

You could effectively go down to 19 lands without issue, seeing as your curve is low. Also consider Forked Bolt and/or Searing Blaze (excellent with all your fetches), as removal is important in the format.

What's your meta like? For Twin, Combust is good alongside your Rakdos Charm. You'll need a way to get rid of enchantments, namely Leyline of Sanctity. Splashing for Destructive Revelry is amazing, as it can also deal with artifacts.

I don't like Treasure Cruise in unison with Grim Lavamancer. I would cut Lavamancer for Goblin Guide.

I'd say -2x Grim Lavamancer and +2x Eidolon of the Great Revel or Goblin Guide. The lavamancer makes Treasure Cruise much worse, whereas the other 2 have obvious benefits. I'd also suggest -2x Blightning and +2x Rift Bolt. Rift Bolt can be cast for 1, Blightning for 3, meaning you have to run 20 land if you run 4x Blightning. If you drop to 2x Blightning and up Rift Bolt to 4 it will allow you to drop to 18 land, letting you run 4 copies of either Goblin Guide or Eidolon of the Great Revel. That will make your deck much more quick, and I think a bit more effective.

i think u could stand to lose two to three lands.

I am going to keep it how it is. I do want to have 3 lands by turn 4, and its tough with 17 to do it consistently.

I really don't know why you won't play Atarka's Command.

The way I look at it, unless there's a huge meta shift, a big reason to play a deck is because it gets more competitive with a new card being printed. Atarka's Command is just that. You've got Destructive Revelry in the board already, so using a R/G Skullcrack (at its worst) should be perfectly fine.