Kiwi, did you find the actual cat only occupied about 3 inches on the O2 sensor side of the larger diameter section of the pipe?
I cut mine on the mid-pipe side first, with plans to cut on the weld at both ends, and noticed it was buried closer to the 02 sensor and header down pipes, so I cut on the weld near the o2 sensor......and found, using my 14" chop saw with a metal blade, that it was much harder to cut through than the other side(is the housing for the actual cat screen/disc titanium), as if I was cutting through titanium or something much harder than the steel header, requiring a slow cut speed.
Unless I truly dulled the blade that much quicker running it at a higher RPM then they call for, since my saw runs higher RPM and using a router router speed control dial will burn up the motor running at a lower RPM.
I did make the first cut without any cutting oil.........which running higher RPM I should have......shame on me, might have killed a $80 blade on one cut.....lol hopefully not.....
Anyway, I cut it open and found the actual honeycomb cat was about a 3 inch thick disc.
I was fortunate enough that exactly where I cut that front weld it cut into the welds for the cat inside the pipe and I taped it out in about 10 seconds with a large square punch.
I pushed it straight out the opposite side of the header pipe (so slip on/mid pipe) side as one solid part.
No honing, turning, drilling, cutting, hacking etc. to get it out.......was so darn easy I felt discouraged that cleaning up the cuts, welds and chamfering/beveling the edges of the cuts, to weld it back together will be the hardest part.......so I took a break from it for a few days.....lol
So a tip to others would be, if you cut it on the front weld, cut it on the weld but closer to the back side of the weld, you might also cut the weld for the inner cat screen and can just push it right out the other end