Header Q's
 

i am about to buy headers i am getting Lt's with EGR & air...so i wont throw codes..
Now do i need to buy an off road Y pipe and if i do will it be emission friendly no codes?

Summit says
Designed for slip-on fit to Pace Setter headers. Has no A.I.R. or EGR provision.
what air and EGR does the stock Y pipe have?

If you don't tune the rear O2s out on an ORY, you'll still throw codes. An alternative is to buy O2 sims for the rear. No cats means not sniffer friendly; if it's tuned and they only do the code scan, you should be fine.

Y-pipes don't have any emissions fittings; they're only on the headers.

You can't buy o2 sims anymore they are illegal. Even if you get a catted Y the cats are so far downstream they will still throw a code so you need to the rear o2's tuned out...

Just tune/have your tuner tune out the o2's completely. Not that big of a deal.

Can the codes from no 02's in the rear be tuned out with a scan tool? Or does it have to be done with the tuning program?

I dont think a scan tool can do it, but I'm not sure. But I know for sure any tuning software can take it out. HPTuners, EFILive, LS1 Edit.....

If by Scan tool, you mean GM Tech II, I think that is capable of doing it, but not worth the money. All of the major tuning software will much cheaper.

I was referring to a general scan tool like a snap-on Motis.