Thats cool, I am pricing gears and posi right now and the cheapest I have found is from www.gearsareus.com

They have the Eaton for my truck at $349 and the Motive Ring and Pinion 3.73's at $139. All shipped it would come out to about $506.

But Summit does that "we beat anyones price" deal and the don't charge for shipping. Not sure how much it will be then.