Do I need a reflash on a 2000 with test pipes?

[Chard]

I am thinking about going catless on my 00 3.2. I was under the car this past weekend and verified I have 2 O2 sensors on each side of the car at the front cats (4 sensors total). I didn't see any sensors at the rear cats.

I am assuming I will get a CEL if I replace the headers with catless ones. Has anyone had success with the angled spacers at the rear O2 bungs? I'm in Hawaii and am not sure where I'd go for a RoW flash here.

Thanks!