Why on earth anyone would want to skimp out on a cog is beyond me. Spend the money, get an EAI, Suntour or Dura-Ace. Search this forum and see the problems that people have had with cheaper cogs (Surlys, Somas, etc) and then decide if spending an extra $10-15 on something that is going to last seems unreasonable. Don't nickle and dime yourself into a whole new set of problems.

m.