sorry to jump on this thread, I have the K-Tec decat and the mount to the manifold is floating/lose unlike the stock cat which is fixed so easier to line up and fit. As a result it's blowing from the join.
Anyone who's done this job, could you do it on your own if you drop the rear part of the subframe to remove the ARB (I'm doing the bushes on that anyway). It's just so tight in there, there's no way you can hold the bolts to stop them rotating when fitting up.