Fast and brutal.
Garruk and the Triumph in there for card draw. Garruk often draws me 8 cards, and the Triumph is useful against control
My sideboard stops everything well enough, Knight of glory for black, Nevermore and Triumph of ferocity for straight control or single win con decks(just the nevermore then). revenge of the hunted for racing, Rest in peace for Reanimator or Grave decks, and intrepid hero for High Damage decks and things like Griselbrand.
All in all my sideboard always helps and I never feel weaker then an opponent afterwards, also you may look into the silverblades Or strangleroots (they kick all kinds of ass)
Yeah, I liked your sideboard and imported some of the cards into mine, since mine wasn't that good. I didn't add Intrepid Hero since I needed the room for 3 Oblivion Rings (which you don't need to care about since you're already running 3 in your main).
I'll try it out on Cockatrice later today.
Also, I didn't add the Revenge of the Hunted because I wanted to keep Thragtusk, who is a good racer himself, giving you life to hold the opponent off while also giving another body after he dies.