Too much...lets just leave it at that. I have gone over the idea of swapping in a manual trans several times, and its way too much money and effort for the money. I just bought a shift kit from transgo for $120 shipped, then I am getting a trans cooler, $50 shipped, and gears $500 shipped and installed. So for under $750, my auto will be faster than most 5 speeds.
You can pursue the idea of swapping in a 5 speed, but in the end, you will realize its not worth it.