Also noticed that the cat to the mid muffler connection is leaking water, steam and exhaust--minor but shouldnt be that way. I have it pushed on enough and it still leaks--clamp is tight. Could it be that I am putting new pipe onto a rusty pipe?

I had this problem with the FCP Groton pipe to cat connection. Turns out it was that the holes in the new flange were oblong, where the original ones were round and smaller. Although it was as tight as I could get it, the flange still leaked. A local exhaust shop saw the problem immediately. The fix was simply to use washers so the bolts wouldn't slip through the oblong holes.

I don't know if that knowledge will help you or not. I seem to remember the rear connection at the cat being a regular exhaust clamp, in which case I think you just need to crank it down more. Use 6-point wrenches so you don't strip out the clamp bolt.