Replacing Bank 2 CAT on XC90 V8

[bumperplates]

Hi,

I'm seeing the dreaded P0430 code after the car was misfiring severely for a few months.

I've replaced the rear O2 Sensor, and that code has returned after a few weeks.

How difficult is it to replace the Bank 2 CAT, and is this possible as a DIY task?

Thank you