What is everybody doing that uses the straight downpipe as far as defeating the o2 sensors? Doesn't it throw codes and check engine light?

 

You don't delete both sensors- you actually want the front one to work still, but that is up in the rear exhaust manifold, so you shouldn't be touching it anyways just doing a DP install.

The only one that you can get rid of is the rear O2. You've got 2 options to get rid of the engine light- buy an O2 emulator which plugs into the old O2's plug and mimmicks a working O2 signal. Or option 2 is to either buy a tuned pcm from a vendor or have someone tune yours to turn it off.