I think Steve said they were using Cometic head gaskets for their single head gaskets. The single [other] gaskets they sell are made on their own laser cutter.
The top end kit they have: ask their Tech Support guys, they will probably tell you whose kit it is. They are good folks there, in my experience. And, if you do have troubles with it in the end, they will want to know about it so they can do something to fix it for others, too.