SPE, H&S, Street Diesel, etc., are all the same kit. Some are just private labeled. It's a terrible design. Capping off a pressurized system with vacuum plugs is just stupid and cheap. The sinister kit is a *bit* better but I use that term loosely because it's still a poor mans fix. Dead heading the system and not allowing full operation as intended is what I believe to be less than ideal. If I felt there was enough market drive, i would finalize and start milling my 6.7 solution kit I have drawn. Unfortunately with no available tuning to new 6.7 owners, it makes the market very small. As well, offering up something that is a quality, american made kit that allows the system to maintain functionality, while others whore out steel bar stock delete plates, would be hard to compete with price wise. I know it would be worth what it's price point was but the market is driven by price shoppers and people don't understand why some things cost more than others until they have bought the cheaper version of "x" with "y" and then experience product failure, resulting in them buying version "x" the second go-round.
.