There have been several sets of Ianettis pop up on Ebay recently for greatly reduced prices. Might want to keep an eye out if that's what you're really looking for.

Jake, you pretty much have it. Though for our application saying there is any disadvantage from a power stand point when going to carbon doesn't hold much water. You should keep the thing above 5k anyway. And the carbon are right in line as far as price. Mazdaspeed is now getting around $300/set for steel seals. Right about what the carbon cost.

Another advantage of the carbon seal is that if you break one you stand a much better chance of not having to throw half the engine in the scrap bin. As long as the failure isn't so comprehensive as to allow the spring to come out of the groove you shouldn't harm the housing or rotor.