OP, The Stryker is a legitimate add-on. If you came from a mildly tuned 5.9L 3rd gen like me, you were less than impressed with the 6.7L absence of throttle response and acceleration rate when passing.
The Stryker def improves on that. Truck drives more like my old 5.9, just without noise and smoke. Like I stated in previous post, the fuel mileage wasnt there after install, but was mainly due to my right foot and idiot factor. Now that ive had it for a while it seems to improve fuel mileage over 1 mpg but not quite 2.... thats just an average of my driving style over the past couple months.
The install went very quick, took longer to round up tools and beer than it did to install. I know of several others that have installed Stryker and love them as well, throttle response is outstanding now...