i want to run a header and no cat . how do i do that without trippen codes. how do i take care of the downstream o2 sensor, without messing up my engine.

 

Why?

 

you can get a tune once you install all of this to delete the rear O2 sensor from the computer

 

will it mess up the readings to the computer, and do i have to take it to a tune shop

 

Mess with computer readings... not so much...

Tune shop to delete code.. yes...

If you get a bung welded into the downpipe you can hook the second o2 sensor into it, and get some spacers to make it think its in a cat... sometimes it works, sometimes it doesnt...

Tuning is the best most effective way.