Where to get speedo gear?

[moparzrule]

First of all, I'm going from 205/60's to 225/50's. So, I have the white gear and want to get the blue gear correct?
And second, where can I buy these gears? Is it a dealer only item? I hate going to the dealers, they charge about 4 times as much as anywhere else. But the thing is sometimes only the dealer has the part so your screwed. So is there anywhere else I can get this speedo gear?