This is a kit for 7.3s and BWD has a twin kit available now, as for the 6.0s BWD has several nice options available and I think he's working on a 6.0 kit not positive.
Black Widow Diesel has several single turbo kits in stock now but no twins. There will be a twins kit in the the future though from what I hear. :woohoo:
Yep you are right they only have singles for 6.0 but the twins are in the works and they move pretty fast on this stuff so shouldn't be long, I know a twin turbo 6.0 would be a beast and sound good too.