[Modern] Goblins

More Goblins!  I don't know if you want any more advice from me :-P but I'll suggest some stuff and you can take whatever you want from it haha.

The first thing I would say is cut the two dragon fodder and run a full set of Mogg War Marshal.  Other than that if you are looking to make cuts I would suggest the tarfires, maybe a couple Goblin Arsonists, although you probably will want more one-drops than you think.  You could do without the full set of wardrivers as well.  You might actually find that the higher cmc guys like Siege-Gang Commander and Krenko are slowing down the deck after some testing, but that will have to be your own decision as I'm sure they are very satisfying to drop off of Warren Instigator.  Cavern of Souls is good, but not necessary for a deck like this if you are looking to shave off some of the monetary value, teetering peaks might be something worth looking into.  Lastly, Aether Vial is another card that, while a staple in Legacy Goblins, does not always find its way into Modern Goblin decks.

Just bear in mind these are only suggestions.  I don't claim to be an authority on the format so I may be off-base on some of this

I'm not going to pretend I'm an expert on modern or goblins.  You're welcome to take or leave any of the intput I'm giving, but here are a few cards to consider:

Personally, I'm not a big fan of the Wardriver - I'd rather have Krenko's Command or Dragon Fodder.  The latter two will each yield you two 1/1 goblins, which is exactly what Wardriver can yield if you get things working correctly - however, Wardriver has the echo cost and ends up either costing 2 CMC for a 1/1 token or 4 CMC for a 1/1 goblin that gives you a 1/1 token when it dies.

Foundry Street Denizen - When will it not be getting pumped?  The potential for a LARGE attack with a one CMC creature is always a plus.

Tattermunge Maniac - You're going to be swinging every turn anyway, so why not swing for two with your one drop?

Hellraiser Goblin - Again, you're going to be doing a LOT of swinging, haste could be huge here as it could easily turn Krenko into a much bigger threat.  This isn't really one you see in a lot of goblin lists out there, but it has promise if used correctly.

Hellrider - If the game even goes long enough to get a 4 drop out, this strikes me as a GREAT option given the all out attacking you'll be doing.

Lastly, things like Dynacharge, Weapon Surge, and Trumpet Blast aren't always considered, but that means they're almost never expected.  Swinging with three 1/1 goblins might easily be let through... turning that into nine damage with an instant could easily be the difference between winning and losing.

Best luck!