Help with explaining headers @ o2 sencors 2003 boxster
 

Ok I've put on new headers with out cats on 2003 Boxster .also a sport muffler . I cant find a answer with the o2 sensors ? What do I do now the headers have plugs that can be taken out for o2 sensors .stop right that will create codes . how do you make this work so possibly no codes appear, Thanks

GOOD LUCK! I've been driving with a CEL for years now--since adding headers. Get yourself a scanner so, like me, you can check from time to time to see if there's any NEW codes that pop up!

First understand that the SMog authorities will castrate you for doing this.It will fail any Visual Test by a Referee. But let's assume you are at peace with that.
It is possible to fit a (new) set of O2 sensors(all 4) using the bungs in your new headers. The rear positions require "extenders" to cheat the system into thinking all is well.
To fit the Bank 1 extender you need to cut a large piece out of a redundant web on the crankcase.
Not pretty or legal, but it should work to extinguish the CEL and you may pass the Smog Test.YEMV.
Please let us know if this works?
What happened to the old Cats? If they are still in good condition they have some value.

I'm not in California, so I don't know the level of nonsense you're dealing with regarding smog. However, there are a couple of options regarding the CEL.
1. Weld in O2 sensor bungs after your existing cats and extend the wires.
2. Get a tune/flash that removes the post-cat sensors. The Porsche ROW flash and the Softronic flash are examples that will work. FWIW, I've got the Softronic and it's kept me O2 CEL free for more than 5 yrs/80,000 miles. It also provides a bit of a power boost.