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

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!

You will indeed get a check engine on the primary cats. The secondary cats are not monitored, so if you choose to go with a different setup other than stock you will not have any problems. People have had success with O2 spacers, however the flash is pretty much guaranteed albeit much more expensive.

Your car will smell bad at idle if you run catless without a tune. It will, though, sound wicked (if you like raspy and waking the neighbors) at high throttle openings. Ask me how I know...

I've searched some more about this and read that some people are plugging the rear o2 bungs and hanging their rear sensors somewhere under the car with success. Can anyone confirm that the rear O2 sensor doesn't affect fuel mixture? That doesn't sound right to me...
I'd hate to try this out only to find that the car runs worse than stock.

Another consideration is getting an aftermarket sport cat but putting it further down the system, basically near where the 2ndary cats are, and hooking up the O2s there. Isn't that how the RoW exhausts are setup? Where could I get extended O2 sensors?

It sounds like regardless of CEL, the catless headers will yield a slight performance gain but will yield even more if paired with a RoW tune, correct?

Trying to source high quality sport cats (i.e. HJS or Emetec 200 cell) can be very ex$pensive. Moreover, you'll need to find a very competent exhaust fabricator who can make you a set of secondary pipes and weld the cats in place. Again, a very ex$pensive proposition. If you're trying to improve upon the oem system, perhaps the most effective way to do this - is with either the M&M Germany or Fabspeed headers /w sport cats, and delete the secondaries altogether.