I run a very Aggro Boros deck (Standard), and I personally run
Boros Elite and War Falcons in my one drop slots. I'd personally drop
Torpid Moloch, unless you're attempting to put up a slow front, and go a longer game. Also the
Suntail hawk is ok, but you'd probably be safe running a
War Falcon in it's place. If you're planning on Battalioning then
Boros Elite for
Warclamp Mastiff. If not leave the Mastiff.
In your two drop slot, it depends on your strategy, but you need to know that running guildmages suggest you want to go longer game. They have a lot of abilities and they're good mana-sinks, but they're not aggressive or particularly strong early on.
Thundersong Trumpeter is just not the best (weak, ability is narrow), and I'd be more inclined to run a 2nd
Wojek Halberdiers over it for the added power and toughness.
The three drops are pretty good.
Guttersnipe is questionable, but he might be ok since you're running so many Instants and Soceries. Ryan Logan is right in
Boros Reckoner being good. He's arguably the best 3 drop available, but he's super costly. If your trying to be competitive then you'd really want to invest in them. If your just casual, it may not be worth the $50 investment.
The
Karoo land you're running is fine (
Boros Garrison) assuming you tap the land you're bouncing for mana before you drop it. Again it goes back to your strategy. I'm Aggro, so I don't like any lands that slow down my deck. If you're more midrange then you can safely run Karoos.
I could go on, but it really depends on what you're wanting to do. If I were you I'd pick between going aggro or mid-range control. Your deck seems to kind of be split between the two. Once you have a game plan in mind it can be a lot easier to shape your deck accordingly.
My Deck:
https://deckstats.net/decks/3370/13354-boros-battalion-beatdown/en