Chrome Mox
This call would most likely be dependent on your particular build. I have been playing a list it is posted on this thread. It is comment number 1500. I would personally suggest against the inclusion of chrome mox. It as you stated allows for explosive starts, but at the expense of your mid-late game. In my experience mid-late game is turns 4-6 for this deck. If you run out of gas you are done. It gives your opponent time to recover, gain life, or smash your face in. I think the loss of two cards (the mox could be burn; and the imprinted card) that could be pointed at your foe's dome is a poor choice.
Crack the Earth and
Misguided Rage
I guess these could potentially work in the correct situation. They are just very situational. If you don't get a turn one crack the earth when you are on the play, your opponent could just sac a land. Same argument goes for the misguided rage. By the time you cast it they could just sac a land. I would opt for the 1-2
Taiga in the main, which would be tutorable by fetches. I would also run
Krosan Grip. I would use this route because it uses less spaces in the sideboard and is the best as far as flexibility goes. Grip can solve many problems that hurt this deck. You might have to wait an extra turn to play your burn, but by then you will have land to unload your hand savagely.