Fitting a decat pipe

I have a KTR 'cat replacement pipe' I would like to fit. I have envisioned it as simply removing the O2 sensor, unclamping the cat from the manifold, sawing the cat off then clamping the new pipe to the centre section with a bit of silicon, clamping the pipe to the manifold and reconnecting the O2 sensor?
 
Hahaha!!!

Much easier on a ramp mate, bloody hard work fiddling about on the driveway.
 
wouldnt say "sawing" was that easy underneath.....better off using a clamp type pipe cutter!