Boostin,
I am going to install a set on my truck in the next month or so. What problem were you seeing just in case it is related? Did you leave the valve and controller in place and just block the exhaust passage?
Mine was having a hesitation mid throttle, lots of blue smoke, and no power.
The kit is designed to replace the cross over, so the valve stays in its place, it still operates, just since the pipe is gone the exhaust is not routed to the intake any more