get rid of frostburn weird an I myself don't like shred freak for the dmg you could do i like using
Gore-House Chainwalker 
definitely get a full set of ash zealot and the noble.
Hellrider 
is a must have for then deck it just helps so much. I myself also would drop
Pyreheart Wolf 
for
Boros Reckoner 
dont get me wrong if you looking at budget then keep the wolf its not a bad card and has its purpose but reckoner is just silly powerful in standard right now.
As far as sideboard drop anything with blue in it. Put in
Skullcrack 
helpful against anything with life gain and thragtusk games. Keep the volcanic strength and take out its pit fight really not going to help you alot in the deck.
in the side-board is almost certainly a bad idea.
