I would not cut the X-member without "bridging" the sides with a permanent weld in piece or a bolt in section. It is a structural piece because it anchors the T-bars.

As for the clutch, thats what the Ram tech support guy told me when I was shopping for a disk to fit my Centerforce DF pressure plate 11" (maybe 10.5 is different) and he talked me into one of their clutch sets. I would call the clutch company first to verify.

Some 3550's and TKO's have ford input splines & different shifters so make sure you know what your getting.