cat-bypass woes

[carnutzzz]

Having a couple problems with my cat-bypass install:

1. With the bypass in place and bolted on the front side, the back isn't in a position compatible with my muffler (aftermarket). Trying to muscle it somewhat close moves the muffler and points the tip down into an awkward position.

So, this is hardly plug n play, and I don't see an easy solution where my swapping between cat and no cat can be done without some modifications.

2. My O2 sensor was pretty well stuck into the cat. Removal destroyed the threads on the O2 sensor, and left the threads on the cat looking a little unhealthy- is there an easy fix or should I just replace the cat?

Thanks!

[KCinBR]

make sure the muffler straps are loose, and tighten the bolts a little at a time, alternate between the cat bolts(6) and muffler to cat bolts(3), then tighten the muffler mounting straps. This is what I did to make it all mate up wit no leaks.
Installed a Fabspeed pre-muff(cat) and M&K muffler