Mtg shadow deck help?

You want less creatures and more ways to pump them up.I would add 2 more Unholy Strength or 2 Demonic Strength, or Sinister Strength. Forget Nightmare lash - too slow for this deck. You might also think about replacing Endless Scream with Howl from Beyond - same thing but is an instant and only pumps until end of turn. Finally, lose the Subversion. If you really need the life, throw in Soul Feast - same cost, but a player loses 4 life and you gain 4. Or Drain Life. Finally, you should definitely have Dark Ritual in here. Nothing better than dropping 1, 2 or 3 creatures on your first turn, then throwing 2 Unholy Strengths on turn 2 and swinging for 8 or 9 shadow...

Noooooooo Coat of Arms. Some people still play tribal decks and don't forget that the Arms applies that to every creature that shares a creature type with another in play. Add in a Cabal Coffers if you can afford it.